Introducing Virtual FE dai link by ranj063 · Pull Request #6 · thesofproject/linux

ranj063 · 2018-06-25T20:21:41Z

This set of patches introduces the concept of a virtual FE dai link.
Previously, when trying to enable the hostless pipeline, it was
discovered that the codec does not get enabled and the tone remained inaudible.
Therefore, in such cases, a virtual FE dai link will be used to establish
a connection to the BE dai and enable the codec when the pipeline is triggered.

The virtual FE will be created when a siggen widget is loaded and freed when
the siggen widget is unloaded. It will be used for enabling the BE dai in the
kcontrol IO handler for the kcontrol attached to the siggen by calling
the soc_spcm_runtime_update() method.

Hostless pipelines lack a FE dai that is used to establish a path to the BE and enable the codecs. Virtual FE dai links can be used in such cases to establish a connection to the BE. This patch adds a new flag named "virtual" to the dai link structure that will be used to check if a dai link is virtual. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

This patch adds the methods for create a virtual FE dal link and add it to the sound card. It also adds the method to free the virtual FE connected to the card. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

When walking the graph to discover the path from the virtual FE to the BE, there is only one widget in the path. Do not remove this BE widget from the list, so it can be used to connect with the virtual FE dai link. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

…irtual dai link Virtual FE dai links should be manually set to running state by default with a pcm runtime. The active count of their cpu_dai and codec_dai's should also be updated. This is required to establish FE-BE connection and enable the BE DAI when the dpcm runtime is updated. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

Virtual FE dai links do not need to register the pcm device. So just create the empty pcm device and substream in the requested direction. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

the soc_dpcm_runtime_update() method will be called to establish a connection to the BE and enable the codec. So make this method accessible to modules. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

ranj063 · 2018-06-25T21:13:42Z

Sorry, I've got issues with my github fork. let me re-submit this in a bit.

commit a5ba1d9 upstream. We have reports of the following crash: PID: 7 TASK: ffff88085c6d61c0 CPU: 1 COMMAND: "kworker/u25:0" #0 [ffff88085c6db710] machine_kexec at ffffffff81046239 #1 [ffff88085c6db760] crash_kexec at ffffffff810fc248 #2 [ffff88085c6db830] oops_end at ffffffff81008ae7 #3 [ffff88085c6db860] no_context at ffffffff81050b8f thesofproject#4 [ffff88085c6db8b0] __bad_area_nosemaphore at ffffffff81050d75 thesofproject#5 [ffff88085c6db900] bad_area_nosemaphore at ffffffff81050e83 thesofproject#6 [ffff88085c6db910] __do_page_fault at ffffffff8105132e thesofproject#7 [ffff88085c6db9b0] do_page_fault at ffffffff8105152c thesofproject#8 [ffff88085c6db9c0] page_fault at ffffffff81a3f122 [exception RIP: uart_put_char+149] RIP: ffffffff814b67b5 RSP: ffff88085c6dba78 RFLAGS: 00010006 RAX: 0000000000000292 RBX: ffffffff827c5120 RCX: 0000000000000081 RDX: 0000000000000000 RSI: 000000000000005f RDI: ffffffff827c5120 RBP: ffff88085c6dba98 R8: 000000000000012c R9: ffffffff822ea320 R10: ffff88085fe4db04 R11: 0000000000000001 R12: ffff881059f9c000 R13: 0000000000000001 R14: 000000000000005f R15: 0000000000000fba ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 thesofproject#9 [ffff88085c6dbaa0] tty_put_char at ffffffff81497544 thesofproject#10 [ffff88085c6dbac0] do_output_char at ffffffff8149c91c thesofproject#11 [ffff88085c6dbae0] __process_echoes at ffffffff8149cb8b thesofproject#12 [ffff88085c6dbb30] commit_echoes at ffffffff8149cdc2 thesofproject#13 [ffff88085c6dbb60] n_tty_receive_buf_fast at ffffffff8149e49b thesofproject#14 [ffff88085c6dbbc0] __receive_buf at ffffffff8149ef5a thesofproject#15 [ffff88085c6dbc20] n_tty_receive_buf_common at ffffffff8149f016 thesofproject#16 [ffff88085c6dbca0] n_tty_receive_buf2 at ffffffff8149f194 thesofproject#17 [ffff88085c6dbcb0] flush_to_ldisc at ffffffff814a238a thesofproject#18 [ffff88085c6dbd50] process_one_work at ffffffff81090be2 thesofproject#19 [ffff88085c6dbe20] worker_thread at ffffffff81091b4d thesofproject#20 [ffff88085c6dbeb0] kthread at ffffffff81096384 thesofproject#21 [ffff88085c6dbf50] ret_from_fork at ffffffff81a3d69f after slogging through some dissasembly: ffffffff814b6720 <uart_put_char>: ffffffff814b6720: 55 push %rbp ffffffff814b6721: 48 89 e5 mov %rsp,%rbp ffffffff814b6724: 48 83 ec 20 sub $0x20,%rsp ffffffff814b6728: 48 89 1c 24 mov %rbx,(%rsp) ffffffff814b672c: 4c 89 64 24 08 mov %r12,0x8(%rsp) ffffffff814b6731: 4c 89 6c 24 10 mov %r13,0x10(%rsp) ffffffff814b6736: 4c 89 74 24 18 mov %r14,0x18(%rsp) ffffffff814b673b: e8 b0 8e 58 00 callq ffffffff81a3f5f0 <mcount> ffffffff814b6740: 4c 8b a7 88 02 00 00 mov 0x288(%rdi),%r12 ffffffff814b6747: 45 31 ed xor %r13d,%r13d ffffffff814b674a: 41 89 f6 mov %esi,%r14d ffffffff814b674d: 49 83 bc 24 70 01 00 cmpq $0x0,0x170(%r12) ffffffff814b6754: 00 00 ffffffff814b6756: 49 8b 9c 24 80 01 00 mov 0x180(%r12),%rbx ffffffff814b675d: 00 ffffffff814b675e: 74 2f je ffffffff814b678f <uart_put_char+0x6f> ffffffff814b6760: 48 89 df mov %rbx,%rdi ffffffff814b6763: e8 a8 67 58 00 callq ffffffff81a3cf10 <_raw_spin_lock_irqsave> ffffffff814b6768: 41 8b 8c 24 78 01 00 mov 0x178(%r12),%ecx ffffffff814b676f: 00 ffffffff814b6770: 89 ca mov %ecx,%edx ffffffff814b6772: f7 d2 not %edx ffffffff814b6774: 41 03 94 24 7c 01 00 add 0x17c(%r12),%edx ffffffff814b677b: 00 ffffffff814b677c: 81 e2 ff 0f 00 00 and $0xfff,%edx ffffffff814b6782: 75 23 jne ffffffff814b67a7 <uart_put_char+0x87> ffffffff814b6784: 48 89 c6 mov %rax,%rsi ffffffff814b6787: 48 89 df mov %rbx,%rdi ffffffff814b678a: e8 e1 64 58 00 callq ffffffff81a3cc70 <_raw_spin_unlock_irqrestore> ffffffff814b678f: 44 89 e8 mov %r13d,%eax ffffffff814b6792: 48 8b 1c 24 mov (%rsp),%rbx ffffffff814b6796: 4c 8b 64 24 08 mov 0x8(%rsp),%r12 ffffffff814b679b: 4c 8b 6c 24 10 mov 0x10(%rsp),%r13 ffffffff814b67a0: 4c 8b 74 24 18 mov 0x18(%rsp),%r14 ffffffff814b67a5: c9 leaveq ffffffff814b67a6: c3 retq ffffffff814b67a7: 49 8b 94 24 70 01 00 mov 0x170(%r12),%rdx ffffffff814b67ae: 00 ffffffff814b67af: 48 63 c9 movslq %ecx,%rcx ffffffff814b67b2: 41 b5 01 mov $0x1,%r13b ffffffff814b67b5: 44 88 34 0a mov %r14b,(%rdx,%rcx,1) ffffffff814b67b9: 41 8b 94 24 78 01 00 mov 0x178(%r12),%edx ffffffff814b67c0: 00 ffffffff814b67c1: 83 c2 01 add $0x1,%edx ffffffff814b67c4: 81 e2 ff 0f 00 00 and $0xfff,%edx ffffffff814b67ca: 41 89 94 24 78 01 00 mov %edx,0x178(%r12) ffffffff814b67d1: 00 ffffffff814b67d2: eb b0 jmp ffffffff814b6784 <uart_put_char+0x64> ffffffff814b67d4: 66 66 66 2e 0f 1f 84 data32 data32 nopw %cs:0x0(%rax,%rax,1) ffffffff814b67db: 00 00 00 00 00 for our build, this is crashing at: circ->buf[circ->head] = c; Looking in uart_port_startup(), it seems that circ->buf (state->xmit.buf) protected by the "per-port mutex", which based on uart_port_check() is state->port.mutex. Indeed, the lock acquired in uart_put_char() is uport->lock, i.e. not the same lock. Anyway, since the lock is not acquired, if uart_shutdown() is called, the last chunk of that function may release state->xmit.buf before its assigned to null, and cause the race above. To fix it, let's lock uport->lock when allocating/deallocating state->xmit.buf in addition to the per-port mutex. v2: switch to locking uport->lock on allocation/deallocation instead of locking the per-port mutex in uart_put_char. Note that since uport->lock is a spin lock, we have to switch the allocation to GFP_ATOMIC. v3: move the allocation outside the lock, so we can switch back to GFP_KERNEL Signed-off-by: Tycho Andersen <tycho@tycho.ws> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 286e877 upstream. Commit efda1b5 ("acpi, nfit, libnvdimm: fix / harden ars_status output length handling") Introduced additional hardening for ambiguity in the ACPI spec for ars_status output sizing. However, it had a couple of cases mixed up. Where it should have been checking for (and returning) "out_field[1] - 4" it was using "out_field[1] - 8" and vice versa. This caused a four byte discrepancy in the buffer size passed on to the command handler, and in some cases, this caused memory corruption like: ./daxdev-errors.sh: line 76: 24104 Aborted (core dumped) ./daxdev-errors $busdev $region malloc(): memory corruption Program received signal SIGABRT, Aborted. [...] thesofproject#5 0x00007ffff7865a2e in calloc () from /lib64/libc.so.6 thesofproject#6 0x00007ffff7bc2970 in ndctl_bus_cmd_new_ars_status (ars_cap=ars_cap@entry=0x6153b0) at ars.c:136 thesofproject#7 0x0000000000401644 in check_ars_status (check=0x7fffffffdeb0, bus=0x604c20) at daxdev-errors.c:144 thesofproject#8 test_daxdev_clear_error (region_name=<optimized out>, bus_name=<optimized out>) at daxdev-errors.c:332 Cc: <stable@vger.kernel.org> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Lukasz Dorau <lukasz.dorau@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Fixes: efda1b5 ("acpi, nfit, libnvdimm: fix / harden ars_status output length handling") Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-of-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fixes a crash when the report encounters an address that could not be associated with an mmaped region: #0 0x00005555557bdc4a in callchain_srcline (ip=<error reading variable: Cannot access memory at address 0x38>, sym=0x0, map=0x0) at util/machine.c:2329 #1 unwind_entry (entry=entry@entry=0x7fffffff9180, arg=arg@entry=0x7ffff5642498) at util/machine.c:2329 #2 0x00005555558370af in entry (arg=0x7ffff5642498, cb=0x5555557bdb50 <unwind_entry>, thread=<optimized out>, ip=18446744073709551615) at util/unwind-libunwind-local.c:586 #3 get_entries (ui=ui@entry=0x7fffffff9620, cb=0x5555557bdb50 <unwind_entry>, arg=0x7ffff5642498, max_stack=<optimized out>) at util/unwind-libunwind-local.c:703 #4 0x0000555555837192 in _unwind__get_entries (cb=<optimized out>, arg=<optimized out>, thread=<optimized out>, data=<optimized out>, max_stack=<optimized out>) at util/unwind-libunwind-local.c:725 #5 0x00005555557c310f in thread__resolve_callchain_unwind (max_stack=127, sample=0x7fffffff9830, evsel=0x555555c7b3b0, cursor=0x7ffff5642498, thread=0x555555c7f6f0) at util/machine.c:2351 #6 thread__resolve_callchain (thread=0x555555c7f6f0, cursor=0x7ffff5642498, evsel=0x555555c7b3b0, sample=0x7fffffff9830, parent=0x7fffffff97b8, root_al=0x7fffffff9750, max_stack=127) at util/machine.c:2378 #7 0x00005555557ba4ee in sample__resolve_callchain (sample=<optimized out>, cursor=<optimized out>, parent=parent@entry=0x7fffffff97b8, evsel=<optimized out>, al=al@entry=0x7fffffff9750, max_stack=<optimized out>) at util/callchain.c:1085 Signed-off-by: Milian Wolff <milian.wolff@kdab.com> Tested-by: Sandipan Das <sandipan@linux.ibm.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Fixes: 2a9d505 ("perf script: Show correct offsets for DWARF-based unwinding") Link: http://lkml.kernel.org/r/20180926135207.30263-1-milian.wolff@kdab.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

This reverts commit d76c743. While commit d76c743 ("serial: 8250_dw: Fix runtime PM handling") fixes runtime PM handling when using kgdb, it introduces a traceback for everyone else. BUG: sleeping function called from invalid context at /mnt/host/source/src/third_party/kernel/next/drivers/base/power/runtime.c:1034 in_atomic(): 1, irqs_disabled(): 1, pid: 1, name: swapper/0 7 locks held by swapper/0/1: #0: 000000005ec5bc72 (&dev->mutex){....}, at: __driver_attach+0xb5/0x12b #1: 000000005d5fa9e5 (&dev->mutex){....}, at: __device_attach+0x3e/0x15b #2: 0000000047e93286 (serial_mutex){+.+.}, at: serial8250_register_8250_port+0x51/0x8bb #3: 000000003b328f07 (port_mutex){+.+.}, at: uart_add_one_port+0xab/0x8b0 #4: 00000000fa313d4d (&port->mutex){+.+.}, at: uart_add_one_port+0xcc/0x8b0 #5: 00000000090983ca (console_lock){+.+.}, at: vprintk_emit+0xdb/0x217 #6: 00000000c743e583 (console_owner){-...}, at: console_unlock+0x211/0x60f irq event stamp: 735222 __down_trylock_console_sem+0x4a/0x84 console_unlock+0x338/0x60f __do_softirq+0x4a4/0x50d irq_exit+0x64/0xe2 CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc5 #6 Hardware name: Google Caroline/Caroline, BIOS Google_Caroline.7820.286.0 03/15/2017 Call Trace: dump_stack+0x7d/0xbd ___might_sleep+0x238/0x259 __pm_runtime_resume+0x4e/0xa4 ? serial8250_rpm_get+0x2e/0x44 serial8250_console_write+0x44/0x301 ? lock_acquire+0x1b8/0x1fa console_unlock+0x577/0x60f vprintk_emit+0x1f0/0x217 printk+0x52/0x6e register_console+0x43b/0x524 uart_add_one_port+0x672/0x8b0 ? set_io_from_upio+0x150/0x162 serial8250_register_8250_port+0x825/0x8bb dw8250_probe+0x80c/0x8b0 ? dw8250_serial_inq+0x8e/0x8e ? dw8250_check_lcr+0x108/0x108 ? dw8250_runtime_resume+0x5b/0x5b ? dw8250_serial_outq+0xa1/0xa1 ? dw8250_remove+0x115/0x115 platform_drv_probe+0x76/0xc5 really_probe+0x1f1/0x3ee ? driver_allows_async_probing+0x5d/0x5d driver_probe_device+0xd6/0x112 ? driver_allows_async_probing+0x5d/0x5d bus_for_each_drv+0xbe/0xe5 __device_attach+0xdd/0x15b bus_probe_device+0x5a/0x10b device_add+0x501/0x894 ? _raw_write_unlock+0x27/0x3a platform_device_add+0x224/0x2b7 mfd_add_device+0x718/0x75b ? __kmalloc+0x144/0x16a ? mfd_add_devices+0x38/0xdb mfd_add_devices+0x9b/0xdb intel_lpss_probe+0x7d4/0x8ee intel_lpss_pci_probe+0xac/0xd4 pci_device_probe+0x101/0x18e ... Revert the offending patch until a more comprehensive solution is available. Cc: Tony Lindgren <tony@atomide.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Phil Edworthy <phil.edworthy@renesas.com> Fixes: d76c743 ("serial: 8250_dw: Fix runtime PM handling") Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When the function name for an inline frame is invalid, we must not try to demangle this symbol, otherwise we crash with: #0 0x0000555555895c01 in bfd_demangle () #1 0x0000555555823262 in demangle_sym (dso=0x555555d92b90, elf_name=0x0, kmodule=0) at util/symbol-elf.c:215 #2 dso__demangle_sym (dso=dso@entry=0x555555d92b90, kmodule=<optimized out>, kmodule@entry=0, elf_name=elf_name@entry=0x0) at util/symbol-elf.c:400 #3 0x00005555557fef4b in new_inline_sym (funcname=0x0, base_sym=0x555555d92b90, dso=0x555555d92b90) at util/srcline.c:89 #4 inline_list__append_dso_a2l (dso=dso@entry=0x555555c7bb00, node=node@entry=0x555555e31810, sym=sym@entry=0x555555d92b90) at util/srcline.c:264 #5 0x00005555557ff27f in addr2line (dso_name=dso_name@entry=0x555555d92430 "/home/milian/.debug/.build-id/f7/186d14bb94f3c6161c010926da66033d24fce5/elf", addr=addr@entry=2888, file=file@entry=0x0, line=line@entry=0x0, dso=dso@entry=0x555555c7bb00, unwind_inlines=unwind_inlines@entry=true, node=0x555555e31810, sym=0x555555d92b90) at util/srcline.c:313 #6 0x00005555557ffe7c in addr2inlines (sym=0x555555d92b90, dso=0x555555c7bb00, addr=2888, dso_name=0x555555d92430 "/home/milian/.debug/.build-id/f7/186d14bb94f3c6161c010926da66033d24fce5/elf") at util/srcline.c:358 So instead handle the case where we get invalid function names for inlined frames and use a fallback '??' function name instead. While this crash was originally reported by Hadrien for rust code, I can now also reproduce it with trivial C++ code. Indeed, it seems like libbfd fails to interpret the debug information for the inline frame symbol name: $ addr2line -e /home/milian/.debug/.build-id/f7/186d14bb94f3c6161c010926da66033d24fce5/elf -if b48 main /usr/include/c++/8.2.1/complex:610 ?? /usr/include/c++/8.2.1/complex:618 ?? /usr/include/c++/8.2.1/complex:675 ?? /usr/include/c++/8.2.1/complex:685 main /home/milian/projects/kdab/rnd/hotspot/tests/test-clients/cpp-inlining/main.cpp:39 I've reported this bug upstream and also attached a patch there which should fix this issue: https://sourceware.org/bugzilla/show_bug.cgi?id=23715 Reported-by: Hadrien Grasland <grasland@lal.in2p3.fr> Signed-off-by: Milian Wolff <milian.wolff@kdab.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Fixes: a64489c ("perf report: Find the inline stack for a given address") [ The above 'Fixes:' cset is where originally the problem was introduced, i.e. using a2l->funcname without checking if it is NULL, but this current patch fixes the current codebase, i.e. multiple csets were applied after a64489c before the problem was reported by Hadrien ] Link: http://lkml.kernel.org/r/20180926135207.30263-3-milian.wolff@kdab.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

[ Upstream commit f5e2848 ] When enumerating page size definitions to check hardware support, we construct a constant which is (1U << (def->shift - 10)). However, the array of page size definitions is only initalised for various MMU_PAGE_* constants, so it contains a number of 0-initialised elements with def->shift == 0. This means we end up shifting by a very large number, which gives the following UBSan splat: ================================================================================ UBSAN: Undefined behaviour in /home/dja/dev/linux/linux/arch/powerpc/mm/tlb_nohash.c:506:21 shift exponent 4294967286 is too large for 32-bit type 'unsigned int' CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc3-00045-ga604f927b012-dirty thesofproject#6 Call Trace: [c00000000101bc20] [c000000000a13d54] .dump_stack+0xa8/0xec (unreliable) [c00000000101bcb0] [c0000000004f20a8] .ubsan_epilogue+0x18/0x64 [c00000000101bd30] [c0000000004f2b10] .__ubsan_handle_shift_out_of_bounds+0x110/0x1a4 [c00000000101be20] [c000000000d21760] .early_init_mmu+0x1b4/0x5a0 [c00000000101bf10] [c000000000d1ba28] .early_setup+0x100/0x130 [c00000000101bf90] [c000000000000528] start_here_multiplatform+0x68/0x80 ================================================================================ Fix this by first checking if the element exists (shift != 0) before constructing the constant. Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

It was observed that a process blocked indefintely in __fscache_read_or_alloc_page(), waiting for FSCACHE_COOKIE_LOOKING_UP to be cleared via fscache_wait_for_deferred_lookup(). At this time, ->backing_objects was empty, which would normaly prevent __fscache_read_or_alloc_page() from getting to the point of waiting. This implies that ->backing_objects was cleared *after* __fscache_read_or_alloc_page was was entered. When an object is "killed" and then "dropped", FSCACHE_COOKIE_LOOKING_UP is cleared in fscache_lookup_failure(), then KILL_OBJECT and DROP_OBJECT are "called" and only in DROP_OBJECT is ->backing_objects cleared. This leaves a window where something else can set FSCACHE_COOKIE_LOOKING_UP and __fscache_read_or_alloc_page() can start waiting, before ->backing_objects is cleared There is some uncertainty in this analysis, but it seems to be fit the observations. Adding the wake in this patch will be handled correctly by __fscache_read_or_alloc_page(), as it checks if ->backing_objects is empty again, after waiting. Customer which reported the hang, also report that the hang cannot be reproduced with this fix. The backtrace for the blocked process looked like: PID: 29360 TASK: ffff881ff2ac0f80 CPU: 3 COMMAND: "zsh" #0 [ffff881ff43efbf8] schedule at ffffffff815e56f1 #1 [ffff881ff43efc58] bit_wait at ffffffff815e64ed #2 [ffff881ff43efc68] __wait_on_bit at ffffffff815e61b8 #3 [ffff881ff43efca0] out_of_line_wait_on_bit at ffffffff815e625e #4 [ffff881ff43efd08] fscache_wait_for_deferred_lookup at ffffffffa04f2e8f [fscache] #5 [ffff881ff43efd18] __fscache_read_or_alloc_page at ffffffffa04f2ffe [fscache] #6 [ffff881ff43efd58] __nfs_readpage_from_fscache at ffffffffa0679668 [nfs] #7 [ffff881ff43efd78] nfs_readpage at ffffffffa067092b [nfs] #8 [ffff881ff43efda0] generic_file_read_iter at ffffffff81187a73 #9 [ffff881ff43efe50] nfs_file_read at ffffffffa066544b [nfs] #10 [ffff881ff43efe70] __vfs_read at ffffffff811fc756 #11 [ffff881ff43efee8] vfs_read at ffffffff811fccfa #12 [ffff881ff43eff18] sys_read at ffffffff811fda62 #13 [ffff881ff43eff50] entry_SYSCALL_64_fastpath at ffffffff815e986e Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: David Howells <dhowells@redhat.com>

Function graph tracing recurses into itself when stackleak is enabled, causing the ftrace graph selftest to run for up to 90 seconds and trigger the softlockup watchdog. Breakpoint 2, ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:200 200 mcount_get_lr_addr x0 // pointer to function's saved lr (gdb) bt \#0 ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:200 \#1 0xffffff80081d5280 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:153 \#2 0xffffff8008555484 in stackleak_track_stack () at ../kernel/stackleak.c:106 \#3 0xffffff8008421ff8 in ftrace_ops_test (ops=0xffffff8009eaa840 <graph_ops>, ip=18446743524091297036, regs=<optimized out>) at ../kernel/trace/ftrace.c:1507 \#4 0xffffff8008428770 in __ftrace_ops_list_func (regs=<optimized out>, ignored=<optimized out>, parent_ip=<optimized out>, ip=<optimized out>) at ../kernel/trace/ftrace.c:6286 \#5 ftrace_ops_no_ops (ip=18446743524091297036, parent_ip=18446743524091242824) at ../kernel/trace/ftrace.c:6321 \#6 0xffffff80081d5280 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:153 \#7 0xffffff800832fd10 in irq_find_mapping (domain=0xffffffc03fc4bc80, hwirq=27) at ../kernel/irq/irqdomain.c:876 \#8 0xffffff800832294c in __handle_domain_irq (domain=0xffffffc03fc4bc80, hwirq=27, lookup=true, regs=0xffffff800814b840) at ../kernel/irq/irqdesc.c:650 \#9 0xffffff80081d52b4 in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:205 Rework so we mark stackleak_track_stack as notrace Co-developed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Kees Cook <keescook@chromium.org>

The *_frag_reasm() functions are susceptible to miscalculating the byte count of packet fragments in case the truesize of a head buffer changes. The truesize member may be changed by the call to skb_unclone(), leaving the fragment memory limit counter unbalanced even if all fragments are processed. This miscalculation goes unnoticed as long as the network namespace which holds the counter is not destroyed. Should an attempt be made to destroy a network namespace that holds an unbalanced fragment memory limit counter the cleanup of the namespace never finishes. The thread handling the cleanup gets stuck in inet_frags_exit_net() waiting for the percpu counter to reach zero. The thread is usually in running state with a stacktrace similar to: PID: 1073 TASK: ffff880626711440 CPU: 1 COMMAND: "kworker/u48:4" #5 [ffff880621563d48] _raw_spin_lock at ffffffff815f5480 #6 [ffff880621563d48] inet_evict_bucket at ffffffff8158020b #7 [ffff880621563d80] inet_frags_exit_net at ffffffff8158051c #8 [ffff880621563db0] ops_exit_list at ffffffff814f5856 #9 [ffff880621563dd8] cleanup_net at ffffffff814f67c0 #10 [ffff880621563e38] process_one_work at ffffffff81096f14 It is not possible to create new network namespaces, and processes that call unshare() end up being stuck in uninterruptible sleep state waiting to acquire the net_mutex. The bug was observed in the IPv6 netfilter code by Per Sundstrom. I thank him for his analysis of the problem. The parts of this patch that apply to IPv4 and IPv6 fragment reassembly are preemptive measures. Signed-off-by: Jiri Wiesner <jwiesner@suse.com> Reported-by: Per Sundstrom <per.sundstrom@redqube.se> Acked-by: Peter Oskolkov <posk@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>

ibmvnic_reset can create and schedule a reset work item from an IRQ context, so do not use a mutex, which can sleep. Convert the reset work item mutex to a spin lock. Locking debugger generated the trace output below. BUG: sleeping function called from invalid context at kernel/locking/mutex.c:908 in_atomic(): 1, irqs_disabled(): 1, pid: 120, name: kworker/8:1 4 locks held by kworker/8:1/120: #0: 0000000017c05720 ((wq_completion)"events"){+.+.}, at: process_one_work+0x188/0x710 #1: 00000000ace90706 ((linkwatch_work).work){+.+.}, at: process_one_work+0x188/0x710 #2: 000000007632871f (rtnl_mutex){+.+.}, at: rtnl_lock+0x30/0x50 #3: 00000000fc36813a (&(&crq->lock)->rlock){..-.}, at: ibmvnic_tasklet+0x88/0x2010 [ibmvnic] irq event stamp: 26293 hardirqs last enabled at (26292): [<c000000000122468>] tasklet_action_common.isra.12+0x78/0x1c0 hardirqs last disabled at (26293): [<c000000000befce8>] _raw_spin_lock_irqsave+0x48/0xf0 softirqs last enabled at (26288): [<c000000000a8ac78>] dev_deactivate_queue.constprop.28+0xc8/0x160 softirqs last disabled at (26289): [<c0000000000306e0>] call_do_softirq+0x14/0x24 CPU: 8 PID: 120 Comm: kworker/8:1 Kdump: loaded Not tainted 4.20.0-rc6 #6 Workqueue: events linkwatch_event Call Trace: [c0000003fffa7a50] [c000000000bc83e4] dump_stack+0xe8/0x164 (unreliable) [c0000003fffa7aa0] [c00000000015ba0c] ___might_sleep+0x2dc/0x320 [c0000003fffa7b20] [c000000000be960c] __mutex_lock+0x8c/0xb40 [c0000003fffa7c30] [d000000006202ac8] ibmvnic_reset+0x78/0x330 [ibmvnic] [c0000003fffa7cc0] [d0000000062097f4] ibmvnic_tasklet+0x1054/0x2010 [ibmvnic] [c0000003fffa7e00] [c0000000001224c8] tasklet_action_common.isra.12+0xd8/0x1c0 [c0000003fffa7e60] [c000000000bf1238] __do_softirq+0x1a8/0x64c [c0000003fffa7f90] [c0000000000306e0] call_do_softirq+0x14/0x24 [c0000003f3f87980] [c00000000001ba50] do_softirq_own_stack+0x60/0xb0 [c0000003f3f879c0] [c0000000001218a8] do_softirq+0xa8/0x100 [c0000003f3f879f0] [c000000000121a74] __local_bh_enable_ip+0x174/0x180 [c0000003f3f87a60] [c000000000bf003c] _raw_spin_unlock_bh+0x5c/0x80 [c0000003f3f87a90] [c000000000a8ac78] dev_deactivate_queue.constprop.28+0xc8/0x160 [c0000003f3f87ad0] [c000000000a8c8b0] dev_deactivate_many+0xd0/0x520 [c0000003f3f87b70] [c000000000a8cd40] dev_deactivate+0x40/0x60 [c0000003f3f87ba0] [c000000000a5e0c4] linkwatch_do_dev+0x74/0xd0 [c0000003f3f87bd0] [c000000000a5e694] __linkwatch_run_queue+0x1a4/0x1f0 [c0000003f3f87c30] [c000000000a5e728] linkwatch_event+0x48/0x60 [c0000003f3f87c50] [c0000000001444e8] process_one_work+0x238/0x710 [c0000003f3f87d20] [c000000000144a48] worker_thread+0x88/0x4e0 [c0000003f3f87db0] [c00000000014e3a8] kthread+0x178/0x1c0 [c0000003f3f87e20] [c00000000000bfd0] ret_from_kernel_thread+0x5c/0x6c Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>

Commit 9b6f7e1 ("mm: rework memcg kernel stack accounting") will result in fork failing if allocating a kernel stack for a task in dup_task_struct exceeds the kernel memory allowance for that cgroup. Unfortunately, it also results in a crash. This is due to the code jumping to free_stack and calling free_thread_stack when the memcg kernel stack charge fails, but without tsk->stack pointing at the freshly allocated stack. This in turn results in the vfree_atomic in free_thread_stack oopsing with a backtrace like this: #5 [ffffc900244efc88] die at ffffffff8101f0ab #6 [ffffc900244efcb8] do_general_protection at ffffffff8101cb86 #7 [ffffc900244efce0] general_protection at ffffffff818ff082 [exception RIP: llist_add_batch+7] RIP: ffffffff8150d487 RSP: ffffc900244efd98 RFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff88085ef55980 RCX: 0000000000000000 RDX: ffff88085ef55980 RSI: 343834343531203a RDI: 343834343531203a RBP: ffffc900244efd98 R8: 0000000000000001 R9: ffff8808578c3600 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88029f6c21c0 R13: 0000000000000286 R14: ffff880147759b00 R15: 0000000000000000 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #8 [ffffc900244efda0] vfree_atomic at ffffffff811df2c7 #9 [ffffc900244efdb8] copy_process at ffffffff81086e37 #10 [ffffc900244efe98] _do_fork at ffffffff810884e0 #11 [ffffc900244eff10] sys_vfork at ffffffff810887ff #12 [ffffc900244eff20] do_syscall_64 at ffffffff81002a43 RIP: 000000000049b948 RSP: 00007ffcdb307830 RFLAGS: 00000246 RAX: ffffffffffffffda RBX: 0000000000896030 RCX: 000000000049b948 RDX: 0000000000000000 RSI: 00007ffcdb307790 RDI: 00000000005d7421 RBP: 000000000067370f R8: 00007ffcdb3077b0 R9: 000000000001ed00 R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000040 R13: 000000000000000f R14: 0000000000000000 R15: 000000000088d018 ORIG_RAX: 000000000000003a CS: 0033 SS: 002b The simplest fix is to assign tsk->stack right where it is allocated. Link: http://lkml.kernel.org/r/20181214231726.7ee4843c@imladris.surriel.com Fixes: 9b6f7e1 ("mm: rework memcg kernel stack accounting") Signed-off-by: Rik van Riel <riel@surriel.com> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[ Upstream commit ebaf39e ] The *_frag_reasm() functions are susceptible to miscalculating the byte count of packet fragments in case the truesize of a head buffer changes. The truesize member may be changed by the call to skb_unclone(), leaving the fragment memory limit counter unbalanced even if all fragments are processed. This miscalculation goes unnoticed as long as the network namespace which holds the counter is not destroyed. Should an attempt be made to destroy a network namespace that holds an unbalanced fragment memory limit counter the cleanup of the namespace never finishes. The thread handling the cleanup gets stuck in inet_frags_exit_net() waiting for the percpu counter to reach zero. The thread is usually in running state with a stacktrace similar to: PID: 1073 TASK: ffff880626711440 CPU: 1 COMMAND: "kworker/u48:4" thesofproject#5 [ffff880621563d48] _raw_spin_lock at ffffffff815f5480 thesofproject#6 [ffff880621563d48] inet_evict_bucket at ffffffff8158020b thesofproject#7 [ffff880621563d80] inet_frags_exit_net at ffffffff8158051c thesofproject#8 [ffff880621563db0] ops_exit_list at ffffffff814f5856 thesofproject#9 [ffff880621563dd8] cleanup_net at ffffffff814f67c0 thesofproject#10 [ffff880621563e38] process_one_work at ffffffff81096f14 It is not possible to create new network namespaces, and processes that call unshare() end up being stuck in uninterruptible sleep state waiting to acquire the net_mutex. The bug was observed in the IPv6 netfilter code by Per Sundstrom. I thank him for his analysis of the problem. The parts of this patch that apply to IPv4 and IPv6 fragment reassembly are preemptive measures. Signed-off-by: Jiri Wiesner <jwiesner@suse.com> Reported-by: Per Sundstrom <per.sundstrom@redqube.se> Acked-by: Peter Oskolkov <posk@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit c5a94f4 ] It was observed that a process blocked indefintely in __fscache_read_or_alloc_page(), waiting for FSCACHE_COOKIE_LOOKING_UP to be cleared via fscache_wait_for_deferred_lookup(). At this time, ->backing_objects was empty, which would normaly prevent __fscache_read_or_alloc_page() from getting to the point of waiting. This implies that ->backing_objects was cleared *after* __fscache_read_or_alloc_page was was entered. When an object is "killed" and then "dropped", FSCACHE_COOKIE_LOOKING_UP is cleared in fscache_lookup_failure(), then KILL_OBJECT and DROP_OBJECT are "called" and only in DROP_OBJECT is ->backing_objects cleared. This leaves a window where something else can set FSCACHE_COOKIE_LOOKING_UP and __fscache_read_or_alloc_page() can start waiting, before ->backing_objects is cleared There is some uncertainty in this analysis, but it seems to be fit the observations. Adding the wake in this patch will be handled correctly by __fscache_read_or_alloc_page(), as it checks if ->backing_objects is empty again, after waiting. Customer which reported the hang, also report that the hang cannot be reproduced with this fix. The backtrace for the blocked process looked like: PID: 29360 TASK: ffff881ff2ac0f80 CPU: 3 COMMAND: "zsh" #0 [ffff881ff43efbf8] schedule at ffffffff815e56f1 #1 [ffff881ff43efc58] bit_wait at ffffffff815e64ed #2 [ffff881ff43efc68] __wait_on_bit at ffffffff815e61b8 #3 [ffff881ff43efca0] out_of_line_wait_on_bit at ffffffff815e625e thesofproject#4 [ffff881ff43efd08] fscache_wait_for_deferred_lookup at ffffffffa04f2e8f [fscache] thesofproject#5 [ffff881ff43efd18] __fscache_read_or_alloc_page at ffffffffa04f2ffe [fscache] thesofproject#6 [ffff881ff43efd58] __nfs_readpage_from_fscache at ffffffffa0679668 [nfs] thesofproject#7 [ffff881ff43efd78] nfs_readpage at ffffffffa067092b [nfs] thesofproject#8 [ffff881ff43efda0] generic_file_read_iter at ffffffff81187a73 thesofproject#9 [ffff881ff43efe50] nfs_file_read at ffffffffa066544b [nfs] thesofproject#10 [ffff881ff43efe70] __vfs_read at ffffffff811fc756 thesofproject#11 [ffff881ff43efee8] vfs_read at ffffffff811fccfa thesofproject#12 [ffff881ff43eff18] sys_read at ffffffff811fda62 thesofproject#13 [ffff881ff43eff50] entry_SYSCALL_64_fastpath at ffffffff815e986e Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>

When option CONFIG_KASAN is enabled toghether with ftrace, function ftrace_graph_caller() gets in to a recursion, via functions kasan_check_read() and kasan_check_write(). Breakpoint 2, ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179 179 mcount_get_pc x0 // function's pc (gdb) bt #0 ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179 #1 0xffffff90101406c8 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:151 #2 0xffffff90106fd084 in kasan_check_write (p=0xffffffc06c170878, size=4) at ../mm/kasan/common.c:105 #3 0xffffff90104a2464 in atomic_add_return (v=<optimized out>, i=<optimized out>) at ./include/generated/atomic-instrumented.h:71 #4 atomic_inc_return (v=<optimized out>) at ./include/generated/atomic-fallback.h:284 #5 trace_graph_entry (trace=0xffffffc03f5ff380) at ../kernel/trace/trace_functions_graph.c:441 #6 0xffffff9010481774 in trace_graph_entry_watchdog (trace=<optimized out>) at ../kernel/trace/trace_selftest.c:741 #7 0xffffff90104a185c in function_graph_enter (ret=<optimized out>, func=<optimized out>, frame_pointer=18446743799894897728, retp=<optimized out>) at ../kernel/trace/trace_functions_graph.c:196 #8 0xffffff9010140628 in prepare_ftrace_return (self_addr=18446743592948977792, parent=0xffffffc03f5ff418, frame_pointer=18446743799894897728) at ../arch/arm64/kernel/ftrace.c:231 #9 0xffffff90101406f4 in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:182 Backtrace stopped: previous frame identical to this frame (corrupt stack?) (gdb) Rework so that the kasan implementation isn't traced. Link: http://lkml.kernel.org/r/20181212183447.15890-1-anders.roxell@linaro.org Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Acked-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

…_map Detected via gcc's ASan: Direct leak of 2048 byte(s) in 64 object(s) allocated from: 6 #0 0x7f606512e370 in __interceptor_realloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0xee370) 7 #1 0x556b0f1d7ddd in thread_map__realloc util/thread_map.c:43 8 #2 0x556b0f1d84c7 in thread_map__new_by_tid util/thread_map.c:85 9 #3 0x556b0f0e045e in is_event_supported util/parse-events.c:2250 10 #4 0x556b0f0e1aa1 in print_hwcache_events util/parse-events.c:2382 11 #5 0x556b0f0e3231 in print_events util/parse-events.c:2514 12 #6 0x556b0ee0a66e in cmd_list /home/changbin/work/linux/tools/perf/builtin-list.c:58 13 #7 0x556b0f01e0ae in run_builtin /home/changbin/work/linux/tools/perf/perf.c:302 14 #8 0x556b0f01e859 in handle_internal_command /home/changbin/work/linux/tools/perf/perf.c:354 15 #9 0x556b0f01edc8 in run_argv /home/changbin/work/linux/tools/perf/perf.c:398 16 #10 0x556b0f01f71f in main /home/changbin/work/linux/tools/perf/perf.c:520 17 #11 0x7f6062ccf09a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a) Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Fixes: 8989605 ("perf tools: Do not put a variable sized type not at the end of a struct") Link: http://lkml.kernel.org/r/20190316080556.3075-3-changbin.du@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Detected with gcc's ASan: Direct leak of 66 byte(s) in 5 object(s) allocated from: #0 0x7ff3b1f32070 in __interceptor_strdup (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x3b070) #1 0x560c8761034d in collect_config util/config.c:597 #2 0x560c8760d9cb in get_value util/config.c:169 #3 0x560c8760dfd7 in perf_parse_file util/config.c:285 #4 0x560c8760e0d2 in perf_config_from_file util/config.c:476 #5 0x560c876108fd in perf_config_set__init util/config.c:661 #6 0x560c87610c72 in perf_config_set__new util/config.c:709 #7 0x560c87610d2f in perf_config__init util/config.c:718 #8 0x560c87610e5d in perf_config util/config.c:730 #9 0x560c875ddea0 in main /home/changbin/work/linux/tools/perf/perf.c:442 #10 0x7ff3afb8609a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a) Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Taeung Song <treeze.taeung@gmail.com> Fixes: 20105ca ("perf config: Introduce perf_config_set class") Link: http://lkml.kernel.org/r/20190316080556.3075-6-changbin.du@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Detected with gcc's ASan: Direct leak of 4356 byte(s) in 120 object(s) allocated from: #0 0x7ff1a2b5a070 in __interceptor_strdup (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x3b070) #1 0x55719aef4814 in build_id_cache__origname util/build-id.c:215 #2 0x55719af649b6 in print_sdt_events util/parse-events.c:2339 #3 0x55719af66272 in print_events util/parse-events.c:2542 #4 0x55719ad1ecaa in cmd_list /home/changbin/work/linux/tools/perf/builtin-list.c:58 #5 0x55719aec745d in run_builtin /home/changbin/work/linux/tools/perf/perf.c:302 #6 0x55719aec7d1a in handle_internal_command /home/changbin/work/linux/tools/perf/perf.c:354 #7 0x55719aec8184 in run_argv /home/changbin/work/linux/tools/perf/perf.c:398 #8 0x55719aeca41a in main /home/changbin/work/linux/tools/perf/perf.c:520 #9 0x7ff1a07ae09a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a) Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Fixes: 40218da ("perf list: Show SDT and pre-cached events") Link: http://lkml.kernel.org/r/20190316080556.3075-7-changbin.du@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

…r-free issue The evlist should be destroyed before the perf session. Detected with gcc's ASan: ================================================================= ==27350==ERROR: AddressSanitizer: heap-use-after-free on address 0x62b000002e38 at pc 0x5611da276999 bp 0x7ffce8f1d1a0 sp 0x7ffce8f1d190 WRITE of size 8 at 0x62b000002e38 thread T0 #0 0x5611da276998 in __list_del /home/work/linux/tools/include/linux/list.h:89 #1 0x5611da276d4a in __list_del_entry /home/work/linux/tools/include/linux/list.h:102 #2 0x5611da276e77 in list_del_init /home/work/linux/tools/include/linux/list.h:145 #3 0x5611da2781cd in thread__put util/thread.c:130 #4 0x5611da2cc0a8 in __thread__zput util/thread.h:68 #5 0x5611da2d2dcb in hist_entry__delete util/hist.c:1148 #6 0x5611da2cdf91 in hists__delete_entry util/hist.c:337 #7 0x5611da2ce19e in hists__delete_entries util/hist.c:365 #8 0x5611da2db2ab in hists__delete_all_entries util/hist.c:2639 #9 0x5611da2db325 in hists_evsel__exit util/hist.c:2651 #10 0x5611da1c5352 in perf_evsel__exit util/evsel.c:1304 #11 0x5611da1c5390 in perf_evsel__delete util/evsel.c:1309 #12 0x5611da1b35f0 in perf_evlist__purge util/evlist.c:124 #13 0x5611da1b38e2 in perf_evlist__delete util/evlist.c:148 #14 0x5611da069781 in cmd_top /home/changbin/work/linux/tools/perf/builtin-top.c:1645 #15 0x5611da17d038 in run_builtin /home/changbin/work/linux/tools/perf/perf.c:302 #16 0x5611da17d577 in handle_internal_command /home/changbin/work/linux/tools/perf/perf.c:354 #17 0x5611da17d97b in run_argv /home/changbin/work/linux/tools/perf/perf.c:398 #18 0x5611da17e0e9 in main /home/changbin/work/linux/tools/perf/perf.c:520 #19 0x7fdcc970f09a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a) #20 0x5611d9ff35c9 in _start (/home/work/linux/tools/perf/perf+0x3e95c9) 0x62b000002e38 is located 11320 bytes inside of 27448-byte region [0x62b000000200,0x62b000006d38) freed by thread T0 here: #0 0x7fdccb04ab70 in free (/usr/lib/x86_64-linux-gnu/libasan.so.5+0xedb70) #1 0x5611da260df4 in perf_session__delete util/session.c:201 #2 0x5611da063de5 in __cmd_top /home/changbin/work/linux/tools/perf/builtin-top.c:1300 #3 0x5611da06973c in cmd_top /home/changbin/work/linux/tools/perf/builtin-top.c:1642 #4 0x5611da17d038 in run_builtin /home/changbin/work/linux/tools/perf/perf.c:302 #5 0x5611da17d577 in handle_internal_command /home/changbin/work/linux/tools/perf/perf.c:354 #6 0x5611da17d97b in run_argv /home/changbin/work/linux/tools/perf/perf.c:398 #7 0x5611da17e0e9 in main /home/changbin/work/linux/tools/perf/perf.c:520 #8 0x7fdcc970f09a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a) previously allocated by thread T0 here: #0 0x7fdccb04b138 in calloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0xee138) #1 0x5611da26010c in zalloc util/util.h:23 #2 0x5611da260824 in perf_session__new util/session.c:118 #3 0x5611da0633a6 in __cmd_top /home/changbin/work/linux/tools/perf/builtin-top.c:1192 #4 0x5611da06973c in cmd_top /home/changbin/work/linux/tools/perf/builtin-top.c:1642 #5 0x5611da17d038 in run_builtin /home/changbin/work/linux/tools/perf/perf.c:302 #6 0x5611da17d577 in handle_internal_command /home/changbin/work/linux/tools/perf/perf.c:354 #7 0x5611da17d97b in run_argv /home/changbin/work/linux/tools/perf/perf.c:398 #8 0x5611da17e0e9 in main /home/changbin/work/linux/tools/perf/perf.c:520 #9 0x7fdcc970f09a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a) SUMMARY: AddressSanitizer: heap-use-after-free /home/work/linux/tools/include/linux/list.h:89 in __list_del Shadow bytes around the buggy address: 0x0c567fff8570: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c567fff8580: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c567fff8590: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c567fff85a0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c567fff85b0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd =>0x0c567fff85c0: fd fd fd fd fd fd fd[fd]fd fd fd fd fd fd fd fd 0x0c567fff85d0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c567fff85e0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c567fff85f0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c567fff8600: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c567fff8610: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb ==27350==ABORTING Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20190316080556.3075-8-changbin.du@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The array str[] should have six elements. ================================================================= ==4322==ERROR: AddressSanitizer: global-buffer-overflow on address 0x56463844e300 at pc 0x564637e7ad0d bp 0x7f30c8c89d10 sp 0x7f30c8c89d00 READ of size 8 at 0x56463844e300 thread T9 #0 0x564637e7ad0c in __ordered_events__flush util/ordered-events.c:316 #1 0x564637e7b0e4 in ordered_events__flush util/ordered-events.c:338 #2 0x564637c6a57d in process_thread /home/changbin/work/linux/tools/perf/builtin-top.c:1073 #3 0x7f30d173a163 in start_thread (/lib/x86_64-linux-gnu/libpthread.so.0+0x8163) #4 0x7f30cfffbdee in __clone (/lib/x86_64-linux-gnu/libc.so.6+0x11adee) 0x56463844e300 is located 32 bytes to the left of global variable 'flags' defined in 'util/trace-event-parse.c:229:26' (0x56463844e320) of size 192 0x56463844e300 is located 0 bytes to the right of global variable 'str' defined in 'util/ordered-events.c:268:28' (0x56463844e2e0) of size 32 SUMMARY: AddressSanitizer: global-buffer-overflow util/ordered-events.c:316 in __ordered_events__flush Shadow bytes around the buggy address: 0x0ac947081c10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0ac947081c20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0ac947081c30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0ac947081c40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0ac947081c50: 00 00 00 00 00 00 00 00 f9 f9 f9 f9 00 00 00 00 =>0x0ac947081c60:[f9]f9 f9 f9 00 00 00 00 00 00 00 00 00 00 00 00 0x0ac947081c70: 00 00 00 00 00 00 00 00 00 00 00 00 f9 f9 f9 f9 0x0ac947081c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0ac947081c90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0ac947081ca0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0ac947081cb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb Thread T9 created by T0 here: #0 0x7f30d179de5f in __interceptor_pthread_create (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x4ae5f) #1 0x564637c6b954 in __cmd_top /home/changbin/work/linux/tools/perf/builtin-top.c:1253 #2 0x564637c7173c in cmd_top /home/changbin/work/linux/tools/perf/builtin-top.c:1642 #3 0x564637d85038 in run_builtin /home/changbin/work/linux/tools/perf/perf.c:302 #4 0x564637d85577 in handle_internal_command /home/changbin/work/linux/tools/perf/perf.c:354 #5 0x564637d8597b in run_argv /home/changbin/work/linux/tools/perf/perf.c:398 #6 0x564637d860e9 in main /home/changbin/work/linux/tools/perf/perf.c:520 #7 0x7f30cff0509a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a) Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Jiri Olsa <jolsa@kernel.org> Fixes: 16c66bc ("perf top: Add processing thread") Fixes: 68ca5d0 ("perf ordered_events: Add ordered_events__flush_time interface") Link: http://lkml.kernel.org/r/20190316080556.3075-13-changbin.du@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Using gcc's ASan, Changbin reports: ================================================================= ==7494==ERROR: LeakSanitizer: detected memory leaks Direct leak of 48 byte(s) in 1 object(s) allocated from: #0 0x7f0333a89138 in calloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0xee138) #1 0x5625e5330a5e in zalloc util/util.h:23 #2 0x5625e5330a9b in perf_counts__new util/counts.c:10 #3 0x5625e5330ca0 in perf_evsel__alloc_counts util/counts.c:47 #4 0x5625e520d8e5 in __perf_evsel__read_on_cpu util/evsel.c:1505 #5 0x5625e517a985 in perf_evsel__read_on_cpu /home/work/linux/tools/perf/util/evsel.h:347 #6 0x5625e517ad1a in test__openat_syscall_event tests/openat-syscall.c:47 #7 0x5625e51528e6 in run_test tests/builtin-test.c:358 #8 0x5625e5152baf in test_and_print tests/builtin-test.c:388 #9 0x5625e51543fe in __cmd_test tests/builtin-test.c:583 #10 0x5625e515572f in cmd_test tests/builtin-test.c:722 #11 0x5625e51c3fb8 in run_builtin /home/changbin/work/linux/tools/perf/perf.c:302 #12 0x5625e51c44f7 in handle_internal_command /home/changbin/work/linux/tools/perf/perf.c:354 #13 0x5625e51c48fb in run_argv /home/changbin/work/linux/tools/perf/perf.c:398 #14 0x5625e51c5069 in main /home/changbin/work/linux/tools/perf/perf.c:520 #15 0x7f033214d09a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a) Indirect leak of 72 byte(s) in 1 object(s) allocated from: #0 0x7f0333a89138 in calloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0xee138) #1 0x5625e532560d in zalloc util/util.h:23 #2 0x5625e532566b in xyarray__new util/xyarray.c:10 #3 0x5625e5330aba in perf_counts__new util/counts.c:15 #4 0x5625e5330ca0 in perf_evsel__alloc_counts util/counts.c:47 #5 0x5625e520d8e5 in __perf_evsel__read_on_cpu util/evsel.c:1505 #6 0x5625e517a985 in perf_evsel__read_on_cpu /home/work/linux/tools/perf/util/evsel.h:347 #7 0x5625e517ad1a in test__openat_syscall_event tests/openat-syscall.c:47 #8 0x5625e51528e6 in run_test tests/builtin-test.c:358 #9 0x5625e5152baf in test_and_print tests/builtin-test.c:388 #10 0x5625e51543fe in __cmd_test tests/builtin-test.c:583 #11 0x5625e515572f in cmd_test tests/builtin-test.c:722 #12 0x5625e51c3fb8 in run_builtin /home/changbin/work/linux/tools/perf/perf.c:302 #13 0x5625e51c44f7 in handle_internal_command /home/changbin/work/linux/tools/perf/perf.c:354 #14 0x5625e51c48fb in run_argv /home/changbin/work/linux/tools/perf/perf.c:398 #15 0x5625e51c5069 in main /home/changbin/work/linux/tools/perf/perf.c:520 #16 0x7f033214d09a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a) His patch took care of evsel->prev_raw_counts, but the above backtraces are about evsel->counts, so fix that instead. Reported-by: Changbin Du <changbin.du@gmail.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Link: https://lkml.kernel.org/n/tip-hd1x13g59f0nuhe4anxhsmfp@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

…_event_on_all_cpus test ================================================================= ==7497==ERROR: LeakSanitizer: detected memory leaks Direct leak of 40 byte(s) in 1 object(s) allocated from: #0 0x7f0333a88f30 in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0xedf30) #1 0x5625e5326213 in cpu_map__trim_new util/cpumap.c:45 #2 0x5625e5326703 in cpu_map__read util/cpumap.c:103 #3 0x5625e53267ef in cpu_map__read_all_cpu_map util/cpumap.c:120 #4 0x5625e5326915 in cpu_map__new util/cpumap.c:135 #5 0x5625e517b355 in test__openat_syscall_event_on_all_cpus tests/openat-syscall-all-cpus.c:36 #6 0x5625e51528e6 in run_test tests/builtin-test.c:358 #7 0x5625e5152baf in test_and_print tests/builtin-test.c:388 #8 0x5625e51543fe in __cmd_test tests/builtin-test.c:583 #9 0x5625e515572f in cmd_test tests/builtin-test.c:722 #10 0x5625e51c3fb8 in run_builtin /home/changbin/work/linux/tools/perf/perf.c:302 #11 0x5625e51c44f7 in handle_internal_command /home/changbin/work/linux/tools/perf/perf.c:354 #12 0x5625e51c48fb in run_argv /home/changbin/work/linux/tools/perf/perf.c:398 #13 0x5625e51c5069 in main /home/changbin/work/linux/tools/perf/perf.c:520 #14 0x7f033214d09a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a) Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Fixes: f30a79b ("perf tools: Add reference counting for cpu_map object") Link: http://lkml.kernel.org/r/20190316080556.3075-15-changbin.du@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

================================================================= ==7506==ERROR: LeakSanitizer: detected memory leaks Direct leak of 13 byte(s) in 3 object(s) allocated from: #0 0x7f03339d6070 in __interceptor_strdup (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x3b070) #1 0x5625e53aaef0 in expr__find_other util/expr.y:221 #2 0x5625e51bcd3f in test__expr tests/expr.c:52 #3 0x5625e51528e6 in run_test tests/builtin-test.c:358 #4 0x5625e5152baf in test_and_print tests/builtin-test.c:388 #5 0x5625e51543fe in __cmd_test tests/builtin-test.c:583 #6 0x5625e515572f in cmd_test tests/builtin-test.c:722 #7 0x5625e51c3fb8 in run_builtin /home/changbin/work/linux/tools/perf/perf.c:302 #8 0x5625e51c44f7 in handle_internal_command /home/changbin/work/linux/tools/perf/perf.c:354 #9 0x5625e51c48fb in run_argv /home/changbin/work/linux/tools/perf/perf.c:398 #10 0x5625e51c5069 in main /home/changbin/work/linux/tools/perf/perf.c:520 #11 0x7f033214d09a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a) Signed-off-by: Changbin Du <changbin.du@gmail.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Fixes: 0751673 ("perf tools: Add a simple expression parser for JSON") Link: http://lkml.kernel.org/r/20190316080556.3075-16-changbin.du@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Ido Schimmel says: ==================== mlxsw: Various fixes This patch set contains various fixes for mlxsw. Patch #1 splits the init() callback between Spectrum-2 and Spectrum-3 in order to avoid enforcing the same firmware version for both ASICs, as this can't possibly work. Without this patch the driver cannot boot with the Spectrum-3 ASIC. Patches #2-#3 fix a long standing race condition that was recently exposed while testing the driver on an emulator, which is very slow compared to the actual hardware. The problem is explained in detail in the commit messages. Patch #4 fixes a selftest. Patch #5 prevents offloaded qdiscs from presenting a non-zero backlog to the user when the netdev is down. This is done by clearing the cached backlog in the driver when the netdev goes down. Patch #6 fixes qdisc statistics (backlog and tail drops) to also take into account the multicast traffic classes. v2: * Patches #2-#3: use skb_cow_head() instead of skb_unshare() as suggested by Jakub. Remove unnecessary check regarding headroom * Patches #5-#6: new ==================== Signed-off-by: David S. Miller <davem@davemloft.net>

There exists a deadlock with range_cyclic that has existed forever. If we loop around with a bio already built we could deadlock with a writer who has the page locked that we're attempting to write but is waiting on a page in our bio to be written out. The task traces are as follows PID: 1329874 TASK: ffff889ebcdf3800 CPU: 33 COMMAND: "kworker/u113:5" #0 [ffffc900297bb658] __schedule at ffffffff81a4c33f #1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3 #2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42 #3 [ffffc900297bb708] __lock_page at ffffffff811f145b #4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502 #5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684 #6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff #7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0 #8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2 #9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd PID: 2167901 TASK: ffff889dc6a59c00 CPU: 14 COMMAND: "aio-dio-invalid" #0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f #1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3 #2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42 #3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6 #4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7 #5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359 #6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933 #7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8 #8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d #9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032 I used drgn to find the respective pages we were stuck on page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901 page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874 As you can see the kworker is waiting for bit 0 (PG_locked) on index 7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index 8148. aio-dio-invalid has 7680, and the kworker epd looks like the following crash> struct extent_page_data ffffc900297bbbb0 struct extent_page_data { bio = 0xffff889f747ed830, tree = 0xffff889eed6ba448, extent_locked = 0, sync_io = 0 } Probably worth mentioning as well that it waits for writeback of the page to complete while holding a lock on it (at prepare_pages()). Using drgn I walked the bio pages looking for page 0xffffea00fbfc7500 which is the one we're waiting for writeback on bio = Object(prog, 'struct bio', address=0xffff889f747ed830) for i in range(0, bio.bi_vcnt.value_()): bv = bio.bi_io_vec[i] if bv.bv_page.value_() == 0xffffea00fbfc7500: print("FOUND IT") which validated what I suspected. The fix for this is simple, flush the epd before we loop back around to the beginning of the file during writeout. Fixes: b293f02 ("Btrfs: Add writepages support") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>

It is not that hard to trigger lockdep splats by calling printk from under zone->lock. Most of them are false positives caused by lock chains introduced early in the boot process and they do not cause any real problems (although most of the early boot lock dependencies could happen after boot as well). There are some console drivers which do allocate from the printk context as well and those should be fixed. In any case, false positives are not that trivial to workaround and it is far from optimal to lose lockdep functionality for something that is a non-issue. So change has_unmovable_pages() so that it no longer calls dump_page() itself - instead it returns a "struct page *" of the unmovable page back to the caller so that in the case of a has_unmovable_pages() failure, the caller can call dump_page() after releasing zone->lock. Also, make dump_page() is able to report a CMA page as well, so the reason string from has_unmovable_pages() can be removed. Even though has_unmovable_pages doesn't hold any reference to the returned page this should be reasonably safe for the purpose of reporting the page (dump_page) because it cannot be hotremoved in the context of memory unplug. The state of the page might change but that is the case even with the existing code as zone->lock only plays role for free pages. While at it, remove a similar but unnecessary debug-only printk() as well. A sample of one of those lockdep splats is, WARNING: possible circular locking dependency detected ------------------------------------------------------ test.sh/8653 is trying to acquire lock: ffffffff865a4460 (console_owner){-.-.}, at: console_unlock+0x207/0x750 but task is already holding lock: ffff88883fff3c58 (&(&zone->lock)->rlock){-.-.}, at: __offline_isolated_pages+0x179/0x3e0 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&(&zone->lock)->rlock){-.-.}: __lock_acquire+0x5b3/0xb40 lock_acquire+0x126/0x280 _raw_spin_lock+0x2f/0x40 rmqueue_bulk.constprop.21+0xb6/0x1160 get_page_from_freelist+0x898/0x22c0 __alloc_pages_nodemask+0x2f3/0x1cd0 alloc_pages_current+0x9c/0x110 allocate_slab+0x4c6/0x19c0 new_slab+0x46/0x70 ___slab_alloc+0x58b/0x960 __slab_alloc+0x43/0x70 __kmalloc+0x3ad/0x4b0 __tty_buffer_request_room+0x100/0x250 tty_insert_flip_string_fixed_flag+0x67/0x110 pty_write+0xa2/0xf0 n_tty_write+0x36b/0x7b0 tty_write+0x284/0x4c0 __vfs_write+0x50/0xa0 vfs_write+0x105/0x290 redirected_tty_write+0x6a/0xc0 do_iter_write+0x248/0x2a0 vfs_writev+0x106/0x1e0 do_writev+0xd4/0x180 __x64_sys_writev+0x45/0x50 do_syscall_64+0xcc/0x76c entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (&(&port->lock)->rlock){-.-.}: __lock_acquire+0x5b3/0xb40 lock_acquire+0x126/0x280 _raw_spin_lock_irqsave+0x3a/0x50 tty_port_tty_get+0x20/0x60 tty_port_default_wakeup+0xf/0x30 tty_port_tty_wakeup+0x39/0x40 uart_write_wakeup+0x2a/0x40 serial8250_tx_chars+0x22e/0x440 serial8250_handle_irq.part.8+0x14a/0x170 serial8250_default_handle_irq+0x5c/0x90 serial8250_interrupt+0xa6/0x130 __handle_irq_event_percpu+0x78/0x4f0 handle_irq_event_percpu+0x70/0x100 handle_irq_event+0x5a/0x8b handle_edge_irq+0x117/0x370 do_IRQ+0x9e/0x1e0 ret_from_intr+0x0/0x2a cpuidle_enter_state+0x156/0x8e0 cpuidle_enter+0x41/0x70 call_cpuidle+0x5e/0x90 do_idle+0x333/0x370 cpu_startup_entry+0x1d/0x1f start_secondary+0x290/0x330 secondary_startup_64+0xb6/0xc0 -> #1 (&port_lock_key){-.-.}: __lock_acquire+0x5b3/0xb40 lock_acquire+0x126/0x280 _raw_spin_lock_irqsave+0x3a/0x50 serial8250_console_write+0x3e4/0x450 univ8250_console_write+0x4b/0x60 console_unlock+0x501/0x750 vprintk_emit+0x10d/0x340 vprintk_default+0x1f/0x30 vprintk_func+0x44/0xd4 printk+0x9f/0xc5 -> #0 (console_owner){-.-.}: check_prev_add+0x107/0xea0 validate_chain+0x8fc/0x1200 __lock_acquire+0x5b3/0xb40 lock_acquire+0x126/0x280 console_unlock+0x269/0x750 vprintk_emit+0x10d/0x340 vprintk_default+0x1f/0x30 vprintk_func+0x44/0xd4 printk+0x9f/0xc5 __offline_isolated_pages.cold.52+0x2f/0x30a offline_isolated_pages_cb+0x17/0x30 walk_system_ram_range+0xda/0x160 __offline_pages+0x79c/0xa10 offline_pages+0x11/0x20 memory_subsys_offline+0x7e/0xc0 device_offline+0xd5/0x110 state_store+0xc6/0xe0 dev_attr_store+0x3f/0x60 sysfs_kf_write+0x89/0xb0 kernfs_fop_write+0x188/0x240 __vfs_write+0x50/0xa0 vfs_write+0x105/0x290 ksys_write+0xc6/0x160 __x64_sys_write+0x43/0x50 do_syscall_64+0xcc/0x76c entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: console_owner --> &(&port->lock)->rlock --> &(&zone->lock)->rlock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&zone->lock)->rlock); lock(&(&port->lock)->rlock); lock(&(&zone->lock)->rlock); lock(console_owner); *** DEADLOCK *** 9 locks held by test.sh/8653: #0: ffff88839ba7d408 (sb_writers#4){.+.+}, at: vfs_write+0x25f/0x290 #1: ffff888277618880 (&of->mutex){+.+.}, at: kernfs_fop_write+0x128/0x240 #2: ffff8898131fc218 (kn->count#115){.+.+}, at: kernfs_fop_write+0x138/0x240 #3: ffffffff86962a80 (device_hotplug_lock){+.+.}, at: lock_device_hotplug_sysfs+0x16/0x50 #4: ffff8884374f4990 (&dev->mutex){....}, at: device_offline+0x70/0x110 #5: ffffffff86515250 (cpu_hotplug_lock.rw_sem){++++}, at: __offline_pages+0xbf/0xa10 #6: ffffffff867405f0 (mem_hotplug_lock.rw_sem){++++}, at: percpu_down_write+0x87/0x2f0 #7: ffff88883fff3c58 (&(&zone->lock)->rlock){-.-.}, at: __offline_isolated_pages+0x179/0x3e0 #8: ffffffff865a4920 (console_lock){+.+.}, at: vprintk_emit+0x100/0x340 stack backtrace: Hardware name: HPE ProLiant DL560 Gen10/ProLiant DL560 Gen10, BIOS U34 05/21/2019 Call Trace: dump_stack+0x86/0xca print_circular_bug.cold.31+0x243/0x26e check_noncircular+0x29e/0x2e0 check_prev_add+0x107/0xea0 validate_chain+0x8fc/0x1200 __lock_acquire+0x5b3/0xb40 lock_acquire+0x126/0x280 console_unlock+0x269/0x750 vprintk_emit+0x10d/0x340 vprintk_default+0x1f/0x30 vprintk_func+0x44/0xd4 printk+0x9f/0xc5 __offline_isolated_pages.cold.52+0x2f/0x30a offline_isolated_pages_cb+0x17/0x30 walk_system_ram_range+0xda/0x160 __offline_pages+0x79c/0xa10 offline_pages+0x11/0x20 memory_subsys_offline+0x7e/0xc0 device_offline+0xd5/0x110 state_store+0xc6/0xe0 dev_attr_store+0x3f/0x60 sysfs_kf_write+0x89/0xb0 kernfs_fop_write+0x188/0x240 __vfs_write+0x50/0xa0 vfs_write+0x105/0x290 ksys_write+0xc6/0x160 __x64_sys_write+0x43/0x50 do_syscall_64+0xcc/0x76c entry_SYSCALL_64_after_hwframe+0x49/0xbe Link: http://lkml.kernel.org/r/20200117181200.20299-1-cai@lca.pw Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The req->body should be updated before req->state is updated and the order should be guaranteed by a barrier. Otherwise, read_reply() might return req->body = NULL. Below is sample callstack when the issue is reproduced on purpose by reordering the updates of req->body and req->state and adding delay in code between updates of req->state and req->body. [ 22.356105] general protection fault: 0000 [#1] SMP PTI [ 22.361185] CPU: 2 PID: 52 Comm: xenwatch Not tainted 5.5.0xen+ thesofproject#6 [ 22.366727] Hardware name: Xen HVM domU, BIOS ... [ 22.372245] RIP: 0010:_parse_integer_fixup_radix+0x6/0x60 ... ... [ 22.392163] RSP: 0018:ffffb2d64023fdf0 EFLAGS: 00010246 [ 22.395933] RAX: 0000000000000000 RBX: 75746e7562755f6d RCX: 0000000000000000 [ 22.400871] RDX: 0000000000000000 RSI: ffffb2d64023fdfc RDI: 75746e7562755f6d [ 22.405874] RBP: 0000000000000000 R08: 00000000000001e8 R09: 0000000000cdcdcd [ 22.410945] R10: ffffb2d6402ffe00 R11: ffff9d95395eaeb0 R12: ffff9d9535935000 [ 22.417613] R13: ffff9d9526d4a000 R14: ffff9d9526f4f340 R15: ffff9d9537654000 [ 22.423726] FS: 0000000000000000(0000) GS:ffff9d953bc80000(0000) knlGS:0000000000000000 [ 22.429898] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 22.434342] CR2: 000000c4206a9000 CR3: 00000001ea3fc002 CR4: 00000000001606e0 [ 22.439645] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 22.444941] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 22.450342] Call Trace: [ 22.452509] simple_strtoull+0x27/0x70 [ 22.455572] xenbus_transaction_start+0x31/0x50 [ 22.459104] netback_changed+0x76c/0xcc1 [xen_netfront] [ 22.463279] ? find_watch+0x40/0x40 [ 22.466156] xenwatch_thread+0xb4/0x150 [ 22.469309] ? wait_woken+0x80/0x80 [ 22.472198] kthread+0x10e/0x130 [ 22.474925] ? kthread_park+0x80/0x80 [ 22.477946] ret_from_fork+0x35/0x40 [ 22.480968] Modules linked in: xen_kbdfront xen_fbfront(+) xen_netfront xen_blkfront [ 22.486783] ---[ end trace a9222030a747c3f7 ]--- [ 22.490424] RIP: 0010:_parse_integer_fixup_radix+0x6/0x60 The virt_rmb() is added in the 'true' path of test_reply(). The "while" is changed to "do while" so that test_reply() is used as a read memory barrier. Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Link: https://lore.kernel.org/r/20200303221423.21962-1-dongli.zhang@oracle.com Reviewed-by: Julien Grall <jgrall@amazon.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

When experimenting with bpf_send_signal() helper in our production environment (5.2 based), we experienced a deadlock in NMI mode: thesofproject#5 [ffffc9002219f770] queued_spin_lock_slowpath at ffffffff8110be24 thesofproject#6 [ffffc9002219f770] _raw_spin_lock_irqsave at ffffffff81a43012 thesofproject#7 [ffffc9002219f780] try_to_wake_up at ffffffff810e7ecd thesofproject#8 [ffffc9002219f7e0] signal_wake_up_state at ffffffff810c7b55 thesofproject#9 [ffffc9002219f7f0] __send_signal at ffffffff810c8602 thesofproject#10 [ffffc9002219f830] do_send_sig_info at ffffffff810ca31a thesofproject#11 [ffffc9002219f868] bpf_send_signal at ffffffff8119d227 thesofproject#12 [ffffc9002219f988] bpf_overflow_handler at ffffffff811d4140 thesofproject#13 [ffffc9002219f9e0] __perf_event_overflow at ffffffff811d68cf thesofproject#14 [ffffc9002219fa10] perf_swevent_overflow at ffffffff811d6a09 thesofproject#15 [ffffc9002219fa38] ___perf_sw_event at ffffffff811e0f47 thesofproject#16 [ffffc9002219fc30] __schedule at ffffffff81a3e04d thesofproject#17 [ffffc9002219fc90] schedule at ffffffff81a3e219 thesofproject#18 [ffffc9002219fca0] futex_wait_queue_me at ffffffff8113d1b9 thesofproject#19 [ffffc9002219fcd8] futex_wait at ffffffff8113e529 thesofproject#20 [ffffc9002219fdf0] do_futex at ffffffff8113ffbc thesofproject#21 [ffffc9002219fec0] __x64_sys_futex at ffffffff81140d1c thesofproject#22 [ffffc9002219ff38] do_syscall_64 at ffffffff81002602 thesofproject#23 [ffffc9002219ff50] entry_SYSCALL_64_after_hwframe at ffffffff81c00068 The above call stack is actually very similar to an issue reported by Commit eac9153 ("bpf/stackmap: Fix deadlock with rq_lock in bpf_get_stack()") by Song Liu. The only difference is bpf_send_signal() helper instead of bpf_get_stack() helper. The above deadlock is triggered with a perf_sw_event. Similar to Commit eac9153, the below almost identical reproducer used tracepoint point sched/sched_switch so the issue can be easily caught. /* stress_test.c */ #include <stdio.h> #include <stdlib.h> #include <sys/mman.h> #include <pthread.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #define THREAD_COUNT 1000 char *filename; void *worker(void *p) { void *ptr; int fd; char *pptr; fd = open(filename, O_RDONLY); if (fd < 0) return NULL; while (1) { struct timespec ts = {0, 1000 + rand() % 2000}; ptr = mmap(NULL, 4096 * 64, PROT_READ, MAP_PRIVATE, fd, 0); usleep(1); if (ptr == MAP_FAILED) { printf("failed to mmap\n"); break; } munmap(ptr, 4096 * 64); usleep(1); pptr = malloc(1); usleep(1); pptr[0] = 1; usleep(1); free(pptr); usleep(1); nanosleep(&ts, NULL); } close(fd); return NULL; } int main(int argc, char *argv[]) { void *ptr; int i; pthread_t threads[THREAD_COUNT]; if (argc < 2) return 0; filename = argv[1]; for (i = 0; i < THREAD_COUNT; i++) { if (pthread_create(threads + i, NULL, worker, NULL)) { fprintf(stderr, "Error creating thread\n"); return 0; } } for (i = 0; i < THREAD_COUNT; i++) pthread_join(threads[i], NULL); return 0; } and the following command: 1. run `stress_test /bin/ls` in one windown 2. hack bcc trace.py with the following change: --- a/tools/trace.py +++ b/tools/trace.py @@ -513,6 +513,7 @@ BPF_PERF_OUTPUT(%s); __data.tgid = __tgid; __data.pid = __pid; bpf_get_current_comm(&__data.comm, sizeof(__data.comm)); + bpf_send_signal(10); %s %s %s.perf_submit(%s, &__data, sizeof(__data)); 3. in a different window run ./trace.py -p $(pidof stress_test) t:sched:sched_switch The deadlock can be reproduced in our production system. Similar to Song's fix, the fix is to delay sending signal if irqs is disabled to avoid deadlocks involving with rq_lock. With this change, my above stress-test in our production system won't cause deadlock any more. I also implemented a scale-down version of reproducer in the selftest (a subsequent commit). With latest bpf-next, it complains for the following potential deadlock. [ 32.832450] -> thesofproject#1 (&p->pi_lock){-.-.}: [ 32.833100] _raw_spin_lock_irqsave+0x44/0x80 [ 32.833696] task_rq_lock+0x2c/0xa0 [ 32.834182] task_sched_runtime+0x59/0xd0 [ 32.834721] thread_group_cputime+0x250/0x270 [ 32.835304] thread_group_cputime_adjusted+0x2e/0x70 [ 32.835959] do_task_stat+0x8a7/0xb80 [ 32.836461] proc_single_show+0x51/0xb0 ... [ 32.839512] -> #0 (&(&sighand->siglock)->rlock){....}: [ 32.840275] __lock_acquire+0x1358/0x1a20 [ 32.840826] lock_acquire+0xc7/0x1d0 [ 32.841309] _raw_spin_lock_irqsave+0x44/0x80 [ 32.841916] __lock_task_sighand+0x79/0x160 [ 32.842465] do_send_sig_info+0x35/0x90 [ 32.842977] bpf_send_signal+0xa/0x10 [ 32.843464] bpf_prog_bc13ed9e4d3163e3_send_signal_tp_sched+0x465/0x1000 [ 32.844301] trace_call_bpf+0x115/0x270 [ 32.844809] perf_trace_run_bpf_submit+0x4a/0xc0 [ 32.845411] perf_trace_sched_switch+0x10f/0x180 [ 32.846014] __schedule+0x45d/0x880 [ 32.846483] schedule+0x5f/0xd0 ... [ 32.853148] Chain exists of: [ 32.853148] &(&sighand->siglock)->rlock --> &p->pi_lock --> &rq->lock [ 32.853148] [ 32.854451] Possible unsafe locking scenario: [ 32.854451] [ 32.855173] CPU0 CPU1 [ 32.855745] ---- ---- [ 32.856278] lock(&rq->lock); [ 32.856671] lock(&p->pi_lock); [ 32.857332] lock(&rq->lock); [ 32.857999] lock(&(&sighand->siglock)->rlock); Deadlock happens on CPU0 when it tries to acquire &sighand->siglock but it has been held by CPU1 and CPU1 tries to grab &rq->lock and cannot get it. This is not exactly the callstack in our production environment, but sympotom is similar and both locks are using spin_lock_irqsave() to acquire the lock, and both involves rq_lock. The fix to delay sending signal when irq is disabled also fixed this issue. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200304191104.2796501-1-yhs@fb.com

…tify Undefined rproc_ops .kick method in remoteproc driver will result in "Unable to handle kernel NULL pointer dereference" in rproc_virtio_notify, after firmware loading if: 1) .kick method wasn't defined in driver 2) resource_table exists in firmware and has "Virtio device entry" defined Let's refuse to register an rproc-induced virtio device if no kick method was defined for rproc. [ 13.180049][ T415] 8<--- cut here --- [ 13.190558][ T415] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 13.212544][ T415] pgd = (ptrval) [ 13.217052][ T415] [00000000] *pgd=00000000 [ 13.224692][ T415] Internal error: Oops: 80000005 [#1] PREEMPT SMP ARM [ 13.231318][ T415] Modules linked in: rpmsg_char imx_rproc virtio_rpmsg_bus rpmsg_core [last unloaded: imx_rproc] [ 13.241687][ T415] CPU: 0 PID: 415 Comm: unload-load.sh Not tainted 5.5.2-00002-g707df13bbbdd thesofproject#6 [ 13.250561][ T415] Hardware name: Freescale i.MX7 Dual (Device Tree) [ 13.257009][ T415] PC is at 0x0 [ 13.260249][ T415] LR is at rproc_virtio_notify+0x2c/0x54 [ 13.265738][ T415] pc : [<00000000>] lr : [<8050f6b0>] psr: 60010113 [ 13.272702][ T415] sp : b8d47c48 ip : 00000001 fp : bc04de00 [ 13.278625][ T415] r10: bc04c000 r9 : 00000cc0 r8 : b8d46000 [ 13.284548][ T415] r7 : 00000000 r6 : b898f200 r5 : 00000000 r4 : b8a29800 [ 13.291773][ T415] r3 : 00000000 r2 : 990a3ad4 r1 : 00000000 r0 : b8a29800 [ 13.299000][ T415] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 13.306833][ T415] Control: 10c5387d Table: b8b4806a DAC: 00000051 [ 13.313278][ T415] Process unload-load.sh (pid: 415, stack limit = 0x(ptrval)) [ 13.320591][ T415] Stack: (0xb8d47c48 to 0xb8d48000) [ 13.325651][ T415] 7c40: b895b680 00000001 b898f200 803c6430 b895bc80 7f00ae18 [ 13.334531][ T415] 7c60: 00000035 00000000 00000000 b9393200 80b3ed80 00004000 b9393268 bbf5a9a2 [ 13.343410][ T415] 7c80: 00000e00 00000200 00000000 7f00aff0 7f00a014 b895b680 b895b800 990a3ad4 [ 13.352290][ T415] 7ca0: 00000001 b898f210 b898f200 00000000 00000000 7f00e000 00000001 00000000 [ 13.361170][ T415] 7cc0: 00000000 803c62e0 80b2169c 802a0924 b898f210 00000000 00000000 b898f210 [ 13.370049][ T415] 7ce0: 80b9ba44 00000000 80b9ba48 00000000 7f00e000 00000008 80b2169c 80400114 [ 13.378929][ T415] 7d00: 80b2169c 8061fd64 b898f210 7f00e000 80400744 b8d46000 80b21634 80b21634 [ 13.387809][ T415] 7d20: 80b2169c 80400614 80b21634 80400718 7f00e000 00000000 b8d47d7c 80400744 [ 13.396689][ T415] 7d40: b8d46000 80b21634 80b21634 803fe33 b898f254 b80fe76c b8d32e38 990a3ad4 [ 13.405569][ T415] 7d60: fffffff3 b898f210 b8d46000 00000001 b898f254 803ffe7c 80857a90 b898f210 [ 13.414449][ T415] 7d80: 00000001 990a3ad4 b8d46000 b898f210 b898f210 80b17aec b8a29c20 803ff0a4 [ 13.423328][ T415] 7da0: b898f210 00000000 b8d46000 803fb8e0 b898f200 00000000 80b17aec b898f210 [ 13.432209][ T415] 7dc0: b8a29c20 990a3ad4 b895b900 b898f200 8050fb7c 80b17aec b898f210 b8a29c20 [ 13.441088][ T415] 7de0: b8a29800 b895b900 b8a29a04 803c5ec0 b8a29c00 b898f200 b8a29a20 00000007 [ 13.449968][ T415] 7e00: b8a29c20 8050fd78 b8a29800 00000000 b8a29a20 b8a29c0 b8a29820 b8a299d0 [ 13.458848][ T415] 7e20: b895b900 8050e5a4 b8a29800 b8a299d8 b8d46000 b8a299e0 b8a29820 b8a299d0 [ 13.467728][ T415] 7e40: b895b900 8050e008 000041ed 00000000 b8b8c440 b8a299d8 b8a299e0 b8a299d8 [ 13.476608][ T415] 7e60: b8b8c440 990a3ad4 00000000 b8a29820 b8b8c400 00000006 b8a29800 b895b880 [ 13.485487][ T415] 7e80: b8d47f78 00000000 00000000 8050f4b4 00000006 b895b890 b8b8c400 008fbea0 [ 13.494367][ T415] 7ea0: b895b880 8029f53 00000000 00000000 b8d46000 00000006 b8d46000 008fbea0 [ 13.503246][ T415] 7ec0: 8029f434 00000000 b8d46000 00000000 00000000 8021e2e4 0000000a 8061fd0c [ 13.512125][ T415] 7ee0: 0000000a b8af0c00 0000000a b8af0c40 00000001 b8af0c40 00000000 8061f910 [ 13.521005][ T415] 7f00: 0000000a 80240af4 00000002 b8d46000 00000000 8061fd0c 00000002 80232d7c [ 13.529884][ T415] 7f20: 00000000 b8d46000 00000000 990a3ad4 00000000 00000006 b8a62d80 008fbea0 [ 13.538764][ T415] 7f40: b8d47f78 00000000 b8d46000 00000000 00000000 802210c0 b88f2900 00000000 [ 13.547644][ T415] 7f60: b8a62d80 b8a62d80 b8d46000 00000006 008fbea0 80221320 00000000 00000000 [ 13.556524][ T415] 7f80: b8af0c00 990a3ad4 0000006c 008fbea0 76f1cda0 00000004 80101204 00000004 [ 13.565403][ T415] 7fa0: 00000000 80101000 0000006c 008fbea0 00000001 008fbea0 00000006 00000000 [ 13.574283][ T415] 7fc0: 0000006c 008fbea0 76f1cda0 00000004 00000006 00000006 00000000 00000000 [ 13.583162][ T415] 7fe0: 00000004 7ebaf7d0 76eb4c0b 76e3f206 600d0030 00000001 00000000 00000000 [ 13.592056][ T415] [<8050f6b0>] (rproc_virtio_notify) from [<803c6430>] (virtqueue_notify+0x1c/0x34) [ 13.601298][ T415] [<803c6430>] (virtqueue_notify) from [<7f00ae18>] (rpmsg_probe+0x280/0x380 [virtio_rpmsg_bus]) [ 13.611663][ T415] [<7f00ae18>] (rpmsg_probe [virtio_rpmsg_bus]) from [<803c62e0>] (virtio_dev_probe+0x1f8/0x2c4) [ 13.622022][ T415] [<803c62e0>] (virtio_dev_probe) from [<80400114>] (really_probe+0x200/0x450) [ 13.630817][ T415] [<80400114>] (really_probe) from [<80400614>] (driver_probe_device+0x16c/0x1ac) [ 13.639873][ T415] [<80400614>] (driver_probe_device) from [<803fe338>] (bus_for_each_drv+0x84/0xc8) [ 13.649102][ T415] [<803fe338>] (bus_for_each_drv) from [<803ffe7c>] (__device_attach+0xd4/0x164) [ 13.658069][ T415] [<803ffe7c>] (__device_attach) from [<803ff0a4>] (bus_probe_device+0x84/0x8c) [ 13.666950][ T415] [<803ff0a4>] (bus_probe_device) from [<803fb8e0>] (device_add+0x444/0x768) [ 13.675572][ T415] [<803fb8e0>] (device_add) from [<803c5ec0>] (register_virtio_device+0xa4/0xfc) [ 13.684541][ T415] [<803c5ec0>] (register_virtio_device) from [<8050fd78>] (rproc_add_virtio_dev+0xcc/0x1b8) [ 13.694466][ T415] [<8050fd78>] (rproc_add_virtio_dev) from [<8050e5a4>] (rproc_start+0x148/0x200) [ 13.703521][ T415] [<8050e5a4>] (rproc_start) from [<8050e008>] (rproc_boot+0x384/0x5c0) [ 13.711708][ T415] [<8050e008>] (rproc_boot) from [<8050f4b4>] (state_store+0x3c/0xc8) [ 13.719723][ T415] [<8050f4b4>] (state_store) from [<8029f530>] (kernfs_fop_write+0xfc/0x214) [ 13.728348][ T415] [<8029f530>] (kernfs_fop_write) from [<8021e2e4>] (__vfs_write+0x30/0x1cc) [ 13.736971][ T415] [<8021e2e4>] (__vfs_write) from [<802210c0>] (vfs_write+0xac/0x17c) [ 13.744985][ T415] [<802210c0>] (vfs_write) from [<80221320>] (ksys_write+0x64/0xe4) [ 13.752825][ T415] [<80221320>] (ksys_write) from [<80101000>] (ret_fast_syscall+0x0/0x54) [ 13.761178][ T415] Exception stack(0xb8d47fa8 to 0xb8d47ff0) [ 13.766932][ T415] 7fa0: 0000006c 008fbea0 00000001 008fbea0 00000006 00000000 [ 13.775811][ T415] 7fc0: 0000006c 008fbea0 76f1cda0 00000004 00000006 00000006 00000000 00000000 [ 13.784687][ T415] 7fe0: 00000004 7ebaf7d0 76eb4c0b 76e3f206 [ 13.790442][ T415] Code: bad PC value [ 13.839214][ T415] ---[ end trace 1fe21ecfc9f28852 ]--- Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Nikita Shubin <NShubin@topcon.com> Fixes: 7a18694 ("remoteproc: remove the single rpmsg vdev limitation") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200306072452.24743-1-NShubin@topcon.com Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> (cherry picked from commit 791c13b) BUG=b:152827561 TEST=Connect wifi on Trogdor Signed-off-by: Evan Green <evgreen@chromium.org> Change-Id: I7c829274cbbf09ce73b2134b6ac4d8df226eda76 Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/2130307 Reviewed-by: Sean Paul <seanpaul@chromium.org> Reviewed-by: Matthias Kaehlcke <mka@chromium.org>

Fix tcon use-after-free and NULL ptr deref. Customer system crashes with the following kernel log: [462233.169868] CIFS VFS: Cancelling wait for mid 4894753 cmd: 14 => a QUERY DIR [462233.228045] CIFS VFS: cifs_put_smb_ses: Session Logoff failure rc=-4 [462233.305922] CIFS VFS: cifs_put_smb_ses: Session Logoff failure rc=-4 [462233.306205] CIFS VFS: cifs_put_smb_ses: Session Logoff failure rc=-4 [462233.347060] CIFS VFS: cifs_put_smb_ses: Session Logoff failure rc=-4 [462233.347107] CIFS VFS: Close unmatched open [462233.347113] BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 ... [exception RIP: cifs_put_tcon+0xa0] (this is doing tcon->ses->server) #6 [...] smb2_cancelled_close_fid at ... [cifs] #7 [...] process_one_work at ... #8 [...] worker_thread at ... #9 [...] kthread at ... The most likely explanation we have is: * When we put the last reference of a tcon (refcount=0), we close the cached share root handle. * If closing a handle is interrupted, SMB2_close() will queue a SMB2_close() in a work thread. * The queued object keeps a tcon ref so we bump the tcon refcount, jumping from 0 to 1. * We reach the end of cifs_put_tcon(), we free the tcon object despite it now having a refcount of 1. * The queued work now runs, but the tcon, ses & server was freed in the meantime resulting in a crash. THREAD 1 ======== cifs_put_tcon => tcon refcount reach 0 SMB2_tdis close_shroot_lease close_shroot_lease_locked => if cached root has lease && refcount = 0 smb2_close_cached_fid => if cached root valid SMB2_close => retry close in a thread if interrupted smb2_handle_cancelled_close __smb2_handle_cancelled_close => !! tcon refcount bump 0 => 1 !! INIT_WORK(&cancelled->work, smb2_cancelled_close_fid); queue_work(cifsiod_wq, &cancelled->work) => queue work tconInfoFree(tcon); ==> freed! cifs_put_smb_ses(ses); ==> freed! THREAD 2 (workqueue) ======== smb2_cancelled_close_fid SMB2_close(0, cancelled->tcon, ...); => use-after-free of tcon cifs_put_tcon(cancelled->tcon); => tcon refcount reach 0 second time *CRASH* Fixes: d919131 ("CIFS: Close cached root handle only if it has a lease") Signed-off-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

[ Upstream commit 1bc7896 ] When experimenting with bpf_send_signal() helper in our production environment (5.2 based), we experienced a deadlock in NMI mode: thesofproject#5 [ffffc9002219f770] queued_spin_lock_slowpath at ffffffff8110be24 thesofproject#6 [ffffc9002219f770] _raw_spin_lock_irqsave at ffffffff81a43012 thesofproject#7 [ffffc9002219f780] try_to_wake_up at ffffffff810e7ecd thesofproject#8 [ffffc9002219f7e0] signal_wake_up_state at ffffffff810c7b55 thesofproject#9 [ffffc9002219f7f0] __send_signal at ffffffff810c8602 thesofproject#10 [ffffc9002219f830] do_send_sig_info at ffffffff810ca31a thesofproject#11 [ffffc9002219f868] bpf_send_signal at ffffffff8119d227 thesofproject#12 [ffffc9002219f988] bpf_overflow_handler at ffffffff811d4140 thesofproject#13 [ffffc9002219f9e0] __perf_event_overflow at ffffffff811d68cf thesofproject#14 [ffffc9002219fa10] perf_swevent_overflow at ffffffff811d6a09 thesofproject#15 [ffffc9002219fa38] ___perf_sw_event at ffffffff811e0f47 thesofproject#16 [ffffc9002219fc30] __schedule at ffffffff81a3e04d thesofproject#17 [ffffc9002219fc90] schedule at ffffffff81a3e219 thesofproject#18 [ffffc9002219fca0] futex_wait_queue_me at ffffffff8113d1b9 thesofproject#19 [ffffc9002219fcd8] futex_wait at ffffffff8113e529 thesofproject#20 [ffffc9002219fdf0] do_futex at ffffffff8113ffbc thesofproject#21 [ffffc9002219fec0] __x64_sys_futex at ffffffff81140d1c thesofproject#22 [ffffc9002219ff38] do_syscall_64 at ffffffff81002602 thesofproject#23 [ffffc9002219ff50] entry_SYSCALL_64_after_hwframe at ffffffff81c00068 The above call stack is actually very similar to an issue reported by Commit eac9153 ("bpf/stackmap: Fix deadlock with rq_lock in bpf_get_stack()") by Song Liu. The only difference is bpf_send_signal() helper instead of bpf_get_stack() helper. The above deadlock is triggered with a perf_sw_event. Similar to Commit eac9153, the below almost identical reproducer used tracepoint point sched/sched_switch so the issue can be easily caught. /* stress_test.c */ #include <stdio.h> #include <stdlib.h> #include <sys/mman.h> #include <pthread.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #define THREAD_COUNT 1000 char *filename; void *worker(void *p) { void *ptr; int fd; char *pptr; fd = open(filename, O_RDONLY); if (fd < 0) return NULL; while (1) { struct timespec ts = {0, 1000 + rand() % 2000}; ptr = mmap(NULL, 4096 * 64, PROT_READ, MAP_PRIVATE, fd, 0); usleep(1); if (ptr == MAP_FAILED) { printf("failed to mmap\n"); break; } munmap(ptr, 4096 * 64); usleep(1); pptr = malloc(1); usleep(1); pptr[0] = 1; usleep(1); free(pptr); usleep(1); nanosleep(&ts, NULL); } close(fd); return NULL; } int main(int argc, char *argv[]) { void *ptr; int i; pthread_t threads[THREAD_COUNT]; if (argc < 2) return 0; filename = argv[1]; for (i = 0; i < THREAD_COUNT; i++) { if (pthread_create(threads + i, NULL, worker, NULL)) { fprintf(stderr, "Error creating thread\n"); return 0; } } for (i = 0; i < THREAD_COUNT; i++) pthread_join(threads[i], NULL); return 0; } and the following command: 1. run `stress_test /bin/ls` in one windown 2. hack bcc trace.py with the following change: # --- a/tools/trace.py # +++ b/tools/trace.py @@ -513,6 +513,7 @@ BPF_PERF_OUTPUT(%s); __data.tgid = __tgid; __data.pid = __pid; bpf_get_current_comm(&__data.comm, sizeof(__data.comm)); + bpf_send_signal(10); %s %s %s.perf_submit(%s, &__data, sizeof(__data)); 3. in a different window run ./trace.py -p $(pidof stress_test) t:sched:sched_switch The deadlock can be reproduced in our production system. Similar to Song's fix, the fix is to delay sending signal if irqs is disabled to avoid deadlocks involving with rq_lock. With this change, my above stress-test in our production system won't cause deadlock any more. I also implemented a scale-down version of reproducer in the selftest (a subsequent commit). With latest bpf-next, it complains for the following potential deadlock. [ 32.832450] -> #1 (&p->pi_lock){-.-.}: [ 32.833100] _raw_spin_lock_irqsave+0x44/0x80 [ 32.833696] task_rq_lock+0x2c/0xa0 [ 32.834182] task_sched_runtime+0x59/0xd0 [ 32.834721] thread_group_cputime+0x250/0x270 [ 32.835304] thread_group_cputime_adjusted+0x2e/0x70 [ 32.835959] do_task_stat+0x8a7/0xb80 [ 32.836461] proc_single_show+0x51/0xb0 ... [ 32.839512] -> #0 (&(&sighand->siglock)->rlock){....}: [ 32.840275] __lock_acquire+0x1358/0x1a20 [ 32.840826] lock_acquire+0xc7/0x1d0 [ 32.841309] _raw_spin_lock_irqsave+0x44/0x80 [ 32.841916] __lock_task_sighand+0x79/0x160 [ 32.842465] do_send_sig_info+0x35/0x90 [ 32.842977] bpf_send_signal+0xa/0x10 [ 32.843464] bpf_prog_bc13ed9e4d3163e3_send_signal_tp_sched+0x465/0x1000 [ 32.844301] trace_call_bpf+0x115/0x270 [ 32.844809] perf_trace_run_bpf_submit+0x4a/0xc0 [ 32.845411] perf_trace_sched_switch+0x10f/0x180 [ 32.846014] __schedule+0x45d/0x880 [ 32.846483] schedule+0x5f/0xd0 ... [ 32.853148] Chain exists of: [ 32.853148] &(&sighand->siglock)->rlock --> &p->pi_lock --> &rq->lock [ 32.853148] [ 32.854451] Possible unsafe locking scenario: [ 32.854451] [ 32.855173] CPU0 CPU1 [ 32.855745] ---- ---- [ 32.856278] lock(&rq->lock); [ 32.856671] lock(&p->pi_lock); [ 32.857332] lock(&rq->lock); [ 32.857999] lock(&(&sighand->siglock)->rlock); Deadlock happens on CPU0 when it tries to acquire &sighand->siglock but it has been held by CPU1 and CPU1 tries to grab &rq->lock and cannot get it. This is not exactly the callstack in our production environment, but sympotom is similar and both locks are using spin_lock_irqsave() to acquire the lock, and both involves rq_lock. The fix to delay sending signal when irq is disabled also fixed this issue. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200304191104.2796501-1-yhs@fb.com Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 791c13b upstream. Undefined rproc_ops .kick method in remoteproc driver will result in "Unable to handle kernel NULL pointer dereference" in rproc_virtio_notify, after firmware loading if: 1) .kick method wasn't defined in driver 2) resource_table exists in firmware and has "Virtio device entry" defined Let's refuse to register an rproc-induced virtio device if no kick method was defined for rproc. [ 13.180049][ T415] 8<--- cut here --- [ 13.190558][ T415] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 13.212544][ T415] pgd = (ptrval) [ 13.217052][ T415] [00000000] *pgd=00000000 [ 13.224692][ T415] Internal error: Oops: 80000005 [#1] PREEMPT SMP ARM [ 13.231318][ T415] Modules linked in: rpmsg_char imx_rproc virtio_rpmsg_bus rpmsg_core [last unloaded: imx_rproc] [ 13.241687][ T415] CPU: 0 PID: 415 Comm: unload-load.sh Not tainted 5.5.2-00002-g707df13bbbdd thesofproject#6 [ 13.250561][ T415] Hardware name: Freescale i.MX7 Dual (Device Tree) [ 13.257009][ T415] PC is at 0x0 [ 13.260249][ T415] LR is at rproc_virtio_notify+0x2c/0x54 [ 13.265738][ T415] pc : [<00000000>] lr : [<8050f6b0>] psr: 60010113 [ 13.272702][ T415] sp : b8d47c48 ip : 00000001 fp : bc04de00 [ 13.278625][ T415] r10: bc04c000 r9 : 00000cc0 r8 : b8d46000 [ 13.284548][ T415] r7 : 00000000 r6 : b898f200 r5 : 00000000 r4 : b8a29800 [ 13.291773][ T415] r3 : 00000000 r2 : 990a3ad4 r1 : 00000000 r0 : b8a29800 [ 13.299000][ T415] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 13.306833][ T415] Control: 10c5387d Table: b8b4806a DAC: 00000051 [ 13.313278][ T415] Process unload-load.sh (pid: 415, stack limit = 0x(ptrval)) [ 13.320591][ T415] Stack: (0xb8d47c48 to 0xb8d48000) [ 13.325651][ T415] 7c40: b895b680 00000001 b898f200 803c6430 b895bc80 7f00ae18 [ 13.334531][ T415] 7c60: 00000035 00000000 00000000 b9393200 80b3ed80 00004000 b9393268 bbf5a9a2 [ 13.343410][ T415] 7c80: 00000e00 00000200 00000000 7f00aff0 7f00a014 b895b680 b895b800 990a3ad4 [ 13.352290][ T415] 7ca0: 00000001 b898f210 b898f200 00000000 00000000 7f00e000 00000001 00000000 [ 13.361170][ T415] 7cc0: 00000000 803c62e0 80b2169c 802a0924 b898f210 00000000 00000000 b898f210 [ 13.370049][ T415] 7ce0: 80b9ba44 00000000 80b9ba48 00000000 7f00e000 00000008 80b2169c 80400114 [ 13.378929][ T415] 7d00: 80b2169c 8061fd64 b898f210 7f00e000 80400744 b8d46000 80b21634 80b21634 [ 13.387809][ T415] 7d20: 80b2169c 80400614 80b21634 80400718 7f00e000 00000000 b8d47d7c 80400744 [ 13.396689][ T415] 7d40: b8d46000 80b21634 80b21634 803fe33 b898f254 b80fe76c b8d32e38 990a3ad4 [ 13.405569][ T415] 7d60: fffffff3 b898f210 b8d46000 00000001 b898f254 803ffe7c 80857a90 b898f210 [ 13.414449][ T415] 7d80: 00000001 990a3ad4 b8d46000 b898f210 b898f210 80b17aec b8a29c20 803ff0a4 [ 13.423328][ T415] 7da0: b898f210 00000000 b8d46000 803fb8e0 b898f200 00000000 80b17aec b898f210 [ 13.432209][ T415] 7dc0: b8a29c20 990a3ad4 b895b900 b898f200 8050fb7c 80b17aec b898f210 b8a29c20 [ 13.441088][ T415] 7de0: b8a29800 b895b900 b8a29a04 803c5ec0 b8a29c00 b898f200 b8a29a20 00000007 [ 13.449968][ T415] 7e00: b8a29c20 8050fd78 b8a29800 00000000 b8a29a20 b8a29c0 b8a29820 b8a299d0 [ 13.458848][ T415] 7e20: b895b900 8050e5a4 b8a29800 b8a299d8 b8d46000 b8a299e0 b8a29820 b8a299d0 [ 13.467728][ T415] 7e40: b895b900 8050e008 000041ed 00000000 b8b8c440 b8a299d8 b8a299e0 b8a299d8 [ 13.476608][ T415] 7e60: b8b8c440 990a3ad4 00000000 b8a29820 b8b8c400 00000006 b8a29800 b895b880 [ 13.485487][ T415] 7e80: b8d47f78 00000000 00000000 8050f4b4 00000006 b895b890 b8b8c400 008fbea0 [ 13.494367][ T415] 7ea0: b895b880 8029f53 00000000 00000000 b8d46000 00000006 b8d46000 008fbea0 [ 13.503246][ T415] 7ec0: 8029f434 00000000 b8d46000 00000000 00000000 8021e2e4 0000000a 8061fd0c [ 13.512125][ T415] 7ee0: 0000000a b8af0c00 0000000a b8af0c40 00000001 b8af0c40 00000000 8061f910 [ 13.521005][ T415] 7f00: 0000000a 80240af4 00000002 b8d46000 00000000 8061fd0c 00000002 80232d7c [ 13.529884][ T415] 7f20: 00000000 b8d46000 00000000 990a3ad4 00000000 00000006 b8a62d80 008fbea0 [ 13.538764][ T415] 7f40: b8d47f78 00000000 b8d46000 00000000 00000000 802210c0 b88f2900 00000000 [ 13.547644][ T415] 7f60: b8a62d80 b8a62d80 b8d46000 00000006 008fbea0 80221320 00000000 00000000 [ 13.556524][ T415] 7f80: b8af0c00 990a3ad4 0000006c 008fbea0 76f1cda0 00000004 80101204 00000004 [ 13.565403][ T415] 7fa0: 00000000 80101000 0000006c 008fbea0 00000001 008fbea0 00000006 00000000 [ 13.574283][ T415] 7fc0: 0000006c 008fbea0 76f1cda0 00000004 00000006 00000006 00000000 00000000 [ 13.583162][ T415] 7fe0: 00000004 7ebaf7d0 76eb4c0b 76e3f206 600d0030 00000001 00000000 00000000 [ 13.592056][ T415] [<8050f6b0>] (rproc_virtio_notify) from [<803c6430>] (virtqueue_notify+0x1c/0x34) [ 13.601298][ T415] [<803c6430>] (virtqueue_notify) from [<7f00ae18>] (rpmsg_probe+0x280/0x380 [virtio_rpmsg_bus]) [ 13.611663][ T415] [<7f00ae18>] (rpmsg_probe [virtio_rpmsg_bus]) from [<803c62e0>] (virtio_dev_probe+0x1f8/0x2c4) [ 13.622022][ T415] [<803c62e0>] (virtio_dev_probe) from [<80400114>] (really_probe+0x200/0x450) [ 13.630817][ T415] [<80400114>] (really_probe) from [<80400614>] (driver_probe_device+0x16c/0x1ac) [ 13.639873][ T415] [<80400614>] (driver_probe_device) from [<803fe338>] (bus_for_each_drv+0x84/0xc8) [ 13.649102][ T415] [<803fe338>] (bus_for_each_drv) from [<803ffe7c>] (__device_attach+0xd4/0x164) [ 13.658069][ T415] [<803ffe7c>] (__device_attach) from [<803ff0a4>] (bus_probe_device+0x84/0x8c) [ 13.666950][ T415] [<803ff0a4>] (bus_probe_device) from [<803fb8e0>] (device_add+0x444/0x768) [ 13.675572][ T415] [<803fb8e0>] (device_add) from [<803c5ec0>] (register_virtio_device+0xa4/0xfc) [ 13.684541][ T415] [<803c5ec0>] (register_virtio_device) from [<8050fd78>] (rproc_add_virtio_dev+0xcc/0x1b8) [ 13.694466][ T415] [<8050fd78>] (rproc_add_virtio_dev) from [<8050e5a4>] (rproc_start+0x148/0x200) [ 13.703521][ T415] [<8050e5a4>] (rproc_start) from [<8050e008>] (rproc_boot+0x384/0x5c0) [ 13.711708][ T415] [<8050e008>] (rproc_boot) from [<8050f4b4>] (state_store+0x3c/0xc8) [ 13.719723][ T415] [<8050f4b4>] (state_store) from [<8029f530>] (kernfs_fop_write+0xfc/0x214) [ 13.728348][ T415] [<8029f530>] (kernfs_fop_write) from [<8021e2e4>] (__vfs_write+0x30/0x1cc) [ 13.736971][ T415] [<8021e2e4>] (__vfs_write) from [<802210c0>] (vfs_write+0xac/0x17c) [ 13.744985][ T415] [<802210c0>] (vfs_write) from [<80221320>] (ksys_write+0x64/0xe4) [ 13.752825][ T415] [<80221320>] (ksys_write) from [<80101000>] (ret_fast_syscall+0x0/0x54) [ 13.761178][ T415] Exception stack(0xb8d47fa8 to 0xb8d47ff0) [ 13.766932][ T415] 7fa0: 0000006c 008fbea0 00000001 008fbea0 00000006 00000000 [ 13.775811][ T415] 7fc0: 0000006c 008fbea0 76f1cda0 00000004 00000006 00000006 00000000 00000000 [ 13.784687][ T415] 7fe0: 00000004 7ebaf7d0 76eb4c0b 76e3f206 [ 13.790442][ T415] Code: bad PC value [ 13.839214][ T415] ---[ end trace 1fe21ecfc9f28852 ]--- Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Nikita Shubin <NShubin@topcon.com> Fixes: 7a18694 ("remoteproc: remove the single rpmsg vdev limitation") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200306072452.24743-1-NShubin@topcon.com Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit a866759 ] This reverts commit 64e62bd. This commit ends up causing some lockdep splats due to trying to grab the payload lock while holding the mgr's lock: [ 54.010099] [ 54.011765] ====================================================== [ 54.018670] WARNING: possible circular locking dependency detected [ 54.025577] 5.5.0-rc6-02274-g77381c23ee63 thesofproject#47 Not tainted [ 54.031610] ------------------------------------------------------ [ 54.038516] kworker/1:6/1040 is trying to acquire lock: [ 54.044354] ffff888272af3228 (&mgr->payload_lock){+.+.}, at: drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4 [ 54.054957] [ 54.054957] but task is already holding lock: [ 54.061473] ffff888272af3060 (&mgr->lock){+.+.}, at: drm_dp_mst_topology_mgr_set_mst+0x3c/0x2e4 [ 54.071193] [ 54.071193] which lock already depends on the new lock. [ 54.071193] [ 54.080334] [ 54.080334] the existing dependency chain (in reverse order) is: [ 54.088697] [ 54.088697] -> #1 (&mgr->lock){+.+.}: [ 54.094440] __mutex_lock+0xc3/0x498 [ 54.099015] drm_dp_mst_topology_get_port_validated+0x25/0x80 [ 54.106018] drm_dp_update_payload_part1+0xa2/0x2e2 [ 54.112051] intel_mst_pre_enable_dp+0x144/0x18f [ 54.117791] intel_encoders_pre_enable+0x63/0x70 [ 54.123532] hsw_crtc_enable+0xa1/0x722 [ 54.128396] intel_update_crtc+0x50/0x194 [ 54.133455] skl_commit_modeset_enables+0x40c/0x540 [ 54.139485] intel_atomic_commit_tail+0x5f7/0x130d [ 54.145418] intel_atomic_commit+0x2c8/0x2d8 [ 54.150770] drm_atomic_helper_set_config+0x5a/0x70 [ 54.156801] drm_mode_setcrtc+0x2ab/0x833 [ 54.161862] drm_ioctl+0x2e5/0x424 [ 54.166242] vfs_ioctl+0x21/0x2f [ 54.170426] do_vfs_ioctl+0x5fb/0x61e [ 54.175096] ksys_ioctl+0x55/0x75 [ 54.179377] __x64_sys_ioctl+0x1a/0x1e [ 54.184146] do_syscall_64+0x5c/0x6d [ 54.188721] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.194946] [ 54.194946] -> #0 (&mgr->payload_lock){+.+.}: [ 54.201463] [ 54.201463] other info that might help us debug this: [ 54.201463] [ 54.210410] Possible unsafe locking scenario: [ 54.210410] [ 54.217025] CPU0 CPU1 [ 54.222082] ---- ---- [ 54.227138] lock(&mgr->lock); [ 54.230643] lock(&mgr->payload_lock); [ 54.237742] lock(&mgr->lock); [ 54.244062] lock(&mgr->payload_lock); [ 54.248346] [ 54.248346] *** DEADLOCK *** [ 54.248346] [ 54.254959] 7 locks held by kworker/1:6/1040: [ 54.259822] #0: ffff888275c4f528 ((wq_completion)events){+.+.}, at: worker_thread+0x455/0x6e2 [ 54.269451] #1: ffffc9000119beb0 ((work_completion)(&(&dev_priv->hotplug.hotplug_work)->work)){+.+.}, at: worker_thread+0x455/0x6e2 [ 54.282768] #2: ffff888272a403f0 (&dev->mode_config.mutex){+.+.}, at: i915_hotplug_work_func+0x4b/0x2be [ 54.293368] #3: ffffffff824fc6c0 (drm_connector_list_iter){.+.+}, at: i915_hotplug_work_func+0x17e/0x2be [ 54.304061] thesofproject#4: ffffc9000119bc58 (crtc_ww_class_acquire){+.+.}, at: drm_helper_probe_detect_ctx+0x40/0xfd [ 54.314855] thesofproject#5: ffff888272a40470 (crtc_ww_class_mutex){+.+.}, at: drm_modeset_lock+0x74/0xe2 [ 54.324385] thesofproject#6: ffff888272af3060 (&mgr->lock){+.+.}, at: drm_dp_mst_topology_mgr_set_mst+0x3c/0x2e4 [ 54.334597] [ 54.334597] stack backtrace: [ 54.339464] CPU: 1 PID: 1040 Comm: kworker/1:6 Not tainted 5.5.0-rc6-02274-g77381c23ee63 thesofproject#47 [ 54.348893] Hardware name: Google Fizz/Fizz, BIOS Google_Fizz.10139.39.0 01/04/2018 [ 54.357451] Workqueue: events i915_hotplug_work_func [ 54.362995] Call Trace: [ 54.365724] dump_stack+0x71/0x9c [ 54.369427] check_noncircular+0x91/0xbc [ 54.373809] ? __lock_acquire+0xc9e/0xf66 [ 54.378286] ? __lock_acquire+0xc9e/0xf66 [ 54.382763] ? lock_acquire+0x175/0x1ac [ 54.387048] ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4 [ 54.393177] ? __mutex_lock+0xc3/0x498 [ 54.397362] ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4 [ 54.403492] ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4 [ 54.409620] ? drm_dp_dpcd_access+0xd9/0x101 [ 54.414390] ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4 [ 54.420517] ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4 [ 54.426645] ? intel_digital_port_connected+0x34d/0x35c [ 54.432482] ? intel_dp_detect+0x227/0x44e [ 54.437056] ? ww_mutex_lock+0x49/0x9a [ 54.441242] ? drm_helper_probe_detect_ctx+0x75/0xfd [ 54.446789] ? intel_encoder_hotplug+0x4b/0x97 [ 54.451752] ? intel_ddi_hotplug+0x61/0x2e0 [ 54.456423] ? mark_held_locks+0x53/0x68 [ 54.460803] ? _raw_spin_unlock_irqrestore+0x3a/0x51 [ 54.466347] ? lockdep_hardirqs_on+0x187/0x1a4 [ 54.471310] ? drm_connector_list_iter_next+0x89/0x9a [ 54.476953] ? i915_hotplug_work_func+0x206/0x2be [ 54.482208] ? worker_thread+0x4d5/0x6e2 [ 54.486587] ? worker_thread+0x455/0x6e2 [ 54.490966] ? queue_work_on+0x64/0x64 [ 54.495151] ? kthread+0x1e9/0x1f1 [ 54.498946] ? queue_work_on+0x64/0x64 [ 54.503130] ? kthread_unpark+0x5e/0x5e [ 54.507413] ? ret_from_fork+0x3a/0x50 The proper fix for this is probably cleanup the VCPI allocations when we're enabling the topology, or on the first payload allocation. For now though, let's just revert. Signed-off-by: Lyude Paul <lyude@redhat.com> Fixes: 64e62bd ("drm/dp_mst: Remove VCPI while disabling topology mgr") Cc: Sean Paul <sean@poorly.run> Cc: Wayne Lin <Wayne.Lin@amd.com> Reviewed-by: Sean Paul <sean@poorly.run> Link: https://patchwork.freedesktop.org/patch/msgid/20200117205149.97262-1-lyude@redhat.com Signed-off-by: Sasha Levin <sashal@kernel.org>

This BUG halt was reported a while back, but the patch somehow got missed: PID: 2879 TASK: c16adaa0 CPU: 1 COMMAND: "sctpn" #0 [f418dd28] crash_kexec at c04a7d8c #1 [f418dd7c] oops_end at c0863e02 #2 [f418dd90] do_invalid_op at c040aaca #3 [f418de28] error_code (via invalid_op) at c08631a5 EAX: f34baac0 EBX: 00000090 ECX: f418deb0 EDX: f5542950 EBP: 00000000 DS: 007b ESI: f34ba800 ES: 007b EDI: f418dea0 GS: 00e0 CS: 0060 EIP: c046fa5e ERR: ffffffff EFLAGS: 00010286 #4 [f418de5c] add_timer at c046fa5e #5 [f418de68] sctp_do_sm at f8db8c77 [sctp] thesofproject#6 [f418df30] sctp_primitive_SHUTDOWN at f8dcc1b5 [sctp] thesofproject#7 [f418df48] inet_shutdown at c080baf9 thesofproject#8 [f418df5c] sys_shutdown at c079eedf thesofproject#9 [f418df7] sys_socketcall at c079fe88 EAX: ffffffda EBX: 0000000d ECX: bfceea90 EDX: 0937af98 DS: 007b ESI: 0000000c ES: 007b EDI: b7150ae4 SS: 007b ESP: bfceea7c EBP: bfceeaa8 GS: 0033 CS: 0073 EIP: b775c424 ERR: 00000066 EFLAGS: 00000282 It appears that the side effect that starts the shutdown timer was processed multiple times, which can happen as multiple paths can trigger it. This of course leads to the BUG halt in add_timer getting called. Fix seems pretty straightforward, just check before the timer is added if its already been started. If it has mod the timer instead to min(current expiration, new expiration) Its been tested but not confirmed to fix the problem, as the issue has only occured in production environments where test kernels are enjoined from being installed. It appears to be a sane fix to me though. Also, recentely, Jere found a reproducer posted on list to confirm that this resolves the issues Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: Vlad Yasevich <vyasevich@gmail.com> CC: "David S. Miller" <davem@davemloft.net> CC: jere.leppanen@nokia.com CC: marcelo.leitner@gmail.com CC: netdev@vger.kernel.org Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>

[ Upstream commit 20a785a ] This BUG halt was reported a while back, but the patch somehow got missed: PID: 2879 TASK: c16adaa0 CPU: 1 COMMAND: "sctpn" #0 [f418dd28] crash_kexec at c04a7d8c thesofproject#1 [f418dd7c] oops_end at c0863e02 thesofproject#2 [f418dd90] do_invalid_op at c040aaca thesofproject#3 [f418de28] error_code (via invalid_op) at c08631a5 EAX: f34baac0 EBX: 00000090 ECX: f418deb0 EDX: f5542950 EBP: 00000000 DS: 007b ESI: f34ba800 ES: 007b EDI: f418dea0 GS: 00e0 CS: 0060 EIP: c046fa5e ERR: ffffffff EFLAGS: 00010286 thesofproject#4 [f418de5c] add_timer at c046fa5e thesofproject#5 [f418de68] sctp_do_sm at f8db8c77 [sctp] thesofproject#6 [f418df30] sctp_primitive_SHUTDOWN at f8dcc1b5 [sctp] thesofproject#7 [f418df48] inet_shutdown at c080baf9 thesofproject#8 [f418df5c] sys_shutdown at c079eedf thesofproject#9 [f418df7] sys_socketcall at c079fe88 EAX: ffffffda EBX: 0000000d ECX: bfceea90 EDX: 0937af98 DS: 007b ESI: 0000000c ES: 007b EDI: b7150ae4 SS: 007b ESP: bfceea7c EBP: bfceeaa8 GS: 0033 CS: 0073 EIP: b775c424 ERR: 00000066 EFLAGS: 00000282 It appears that the side effect that starts the shutdown timer was processed multiple times, which can happen as multiple paths can trigger it. This of course leads to the BUG halt in add_timer getting called. Fix seems pretty straightforward, just check before the timer is added if its already been started. If it has mod the timer instead to min(current expiration, new expiration) Its been tested but not confirmed to fix the problem, as the issue has only occured in production environments where test kernels are enjoined from being installed. It appears to be a sane fix to me though. Also, recentely, Jere found a reproducer posted on list to confirm that this resolves the issues Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: Vlad Yasevich <vyasevich@gmail.com> CC: "David S. Miller" <davem@davemloft.net> CC: jere.leppanen@nokia.com CC: marcelo.leitner@gmail.com CC: netdev@vger.kernel.org Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

…ct lock In the extreme case, we may wish to wait on an rcu-barrier to reap stale vm to purge the last of the object bindings. However, we are not allowed to use rcu_barrier() beneath the dma_resv (i.e. object) lock and do not take lightly the prospect of unlocking a mutex deep in the bowels of the routine. i915_gem_object_unbind() itself does not need the object lock, and it turns out the callers do not need to the unbind as part of a locked sequence around set-cache-level, so rearrange the code to avoid taking the object lock in the callers. <4> [186.816311] ====================================================== <4> [186.816313] WARNING: possible circular locking dependency detected <4> [186.816316] 5.4.0-rc8-CI-CI_DRM_7486+ thesofproject#1 Tainted: G U <4> [186.816318] ------------------------------------------------------ <4> [186.816320] perf_pmu/1321 is trying to acquire lock: <4> [186.816322] ffff88849487c4d8 (&mm->mmap_sem#2){++++}, at: __might_fault+0x39/0x90 <4> [186.816331] but task is already holding lock: <4> [186.816333] ffffe8ffffa05008 (&cpuctx_mutex){+.+.}, at: perf_event_ctx_lock_nested+0xa9/0x1b0 <4> [186.816339] which lock already depends on the new lock. <4> [186.816341] the existing dependency chain (in reverse order) is: <4> [186.816343] -> thesofproject#6 (&cpuctx_mutex){+.+.}: <4> [186.816349] __mutex_lock+0x9a/0x9d0 <4> [186.816352] perf_event_init_cpu+0xa4/0x140 <4> [186.816357] perf_event_init+0x19d/0x1cd <4> [186.816362] start_kernel+0x372/0x4f4 <4> [186.816365] secondary_startup_64+0xa4/0xb0 <4> [186.816381] -> thesofproject#5 (pmus_lock){+.+.}: <4> [186.816385] __mutex_lock+0x9a/0x9d0 <4> [186.816387] perf_event_init_cpu+0x6b/0x140 <4> [186.816404] cpuhp_invoke_callback+0x9b/0x9d0 <4> [186.816406] _cpu_up+0xa2/0x140 <4> [186.816409] do_cpu_up+0x61/0xa0 <4> [186.816411] smp_init+0x57/0x96 <4> [186.816413] kernel_init_freeable+0xac/0x1c7 <4> [186.816416] kernel_init+0x5/0x100 <4> [186.816419] ret_from_fork+0x24/0x50 <4> [186.816421] -> thesofproject#4 (cpu_hotplug_lock.rw_sem){++++}: <4> [186.816424] cpus_read_lock+0x34/0xd0 <4> [186.816427] rcu_barrier+0xaa/0x190 <4> [186.816429] kernel_init+0x21/0x100 <4> [186.816431] ret_from_fork+0x24/0x50 <4> [186.816433] -> thesofproject#3 (rcu_state.barrier_mutex){+.+.}: <4> [186.816436] __mutex_lock+0x9a/0x9d0 <4> [186.816438] rcu_barrier+0x23/0x190 <4> [186.816502] i915_gem_object_unbind+0x3a6/0x400 [i915] <4> [186.816537] i915_gem_object_set_cache_level+0x32/0x90 [i915] <4> [186.816571] i915_gem_object_pin_to_display_plane+0x5d/0x160 [i915] <4> [186.816612] intel_pin_and_fence_fb_obj+0x9e/0x200 [i915] <4> [186.816679] intel_plane_pin_fb+0x3f/0xd0 [i915] <4> [186.816717] intel_prepare_plane_fb+0x130/0x520 [i915] <4> [186.816722] drm_atomic_helper_prepare_planes+0x85/0x110 <4> [186.816761] intel_atomic_commit+0xc6/0x350 [i915] <4> [186.816764] drm_atomic_helper_update_plane+0xed/0x110 <4> [186.816768] setplane_internal+0x97/0x190 <4> [186.816770] drm_mode_setplane+0xcd/0x190 <4> [186.816773] drm_ioctl_kernel+0xa7/0xf0 <4> [186.816775] drm_ioctl+0x2e1/0x390 <4> [186.816778] do_vfs_ioctl+0xa0/0x6f0 <4> [186.816780] ksys_ioctl+0x35/0x60 <4> [186.816782] __x64_sys_ioctl+0x11/0x20 <4> [186.816785] do_syscall_64+0x4f/0x210 <4> [186.816787] entry_SYSCALL_64_after_hwframe+0x49/0xbe <4> [186.816789] -> thesofproject#2 (reservation_ww_class_mutex){+.+.}: <4> [186.816793] __ww_mutex_lock.constprop.15+0xc3/0x1090 <4> [186.816795] ww_mutex_lock+0x39/0x70 <4> [186.816798] dma_resv_lockdep+0x10e/0x1f7 <4> [186.816800] do_one_initcall+0x58/0x2ff <4> [186.816802] kernel_init_freeable+0x137/0x1c7 <4> [186.816804] kernel_init+0x5/0x100 <4> [186.816806] ret_from_fork+0x24/0x50 <4> [186.816808] -> thesofproject#1 (reservation_ww_class_acquire){+.+.}: <4> [186.816811] dma_resv_lockdep+0xec/0x1f7 <4> [186.816813] do_one_initcall+0x58/0x2ff <4> [186.816815] kernel_init_freeable+0x137/0x1c7 <4> [186.816817] kernel_init+0x5/0x100 <4> [186.816819] ret_from_fork+0x24/0x50 <4> [186.816820] -> #0 (&mm->mmap_sem#2){++++}: <4> [186.816824] __lock_acquire+0x1328/0x15d0 <4> [186.816826] lock_acquire+0xa7/0x1c0 <4> [186.816828] __might_fault+0x63/0x90 <4> [186.816831] _copy_to_user+0x1e/0x80 <4> [186.816834] perf_read+0x200/0x2b0 <4> [186.816836] vfs_read+0x96/0x160 <4> [186.816838] ksys_read+0x9f/0xe0 <4> [186.816839] do_syscall_64+0x4f/0x210 <4> [186.816841] entry_SYSCALL_64_after_hwframe+0x49/0xbe <4> [186.816843] other info that might help us debug this: <4> [186.816846] Chain exists of: &mm->mmap_sem#2 --> pmus_lock --> &cpuctx_mutex <4> [186.816849] Possible unsafe locking scenario: <4> [186.816851] CPU0 CPU1 <4> [186.816853] ---- ---- <4> [186.816854] lock(&cpuctx_mutex); <4> [186.816856] lock(pmus_lock); <4> [186.816858] lock(&cpuctx_mutex); <4> [186.816860] lock(&mm->mmap_sem#2); <4> [186.816861] *** DEADLOCK *** Closes: https://gitlab.freedesktop.org/drm/intel/issues/728 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Andi Shyti <andi.shyti@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191206105527.1130413-5-chris@chris-wilson.co.uk (cherry picked from commit 8b1c78e) BUG=b:152719649 TEST=Test Graphics/Media/Display use cases Signed-off-by: Ap, Kamal <kamal.ap@intel.com> Change-Id: I849dfa640a87a91c9d1f57c40ac2228255f4e3d5

Ziqian reported lockup when adding retprobe on _raw_spin_lock_irqsave. My test was also able to trigger lockdep output: ============================================ WARNING: possible recursive locking detected 5.6.0-rc6+ #6 Not tainted -------------------------------------------- sched-messaging/2767 is trying to acquire lock: ffffffff9a492798 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_hash_lock+0x52/0xa0 but task is already holding lock: ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(kretprobe_table_locks[i].lock)); lock(&(kretprobe_table_locks[i].lock)); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by sched-messaging/2767: #0: ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50 stack backtrace: CPU: 3 PID: 2767 Comm: sched-messaging Not tainted 5.6.0-rc6+ #6 Call Trace: dump_stack+0x96/0xe0 __lock_acquire.cold.57+0x173/0x2b7 ? native_queued_spin_lock_slowpath+0x42b/0x9e0 ? lockdep_hardirqs_on+0x590/0x590 ? __lock_acquire+0xf63/0x4030 lock_acquire+0x15a/0x3d0 ? kretprobe_hash_lock+0x52/0xa0 _raw_spin_lock_irqsave+0x36/0x70 ? kretprobe_hash_lock+0x52/0xa0 kretprobe_hash_lock+0x52/0xa0 trampoline_handler+0xf8/0x940 ? kprobe_fault_handler+0x380/0x380 ? find_held_lock+0x3a/0x1c0 kretprobe_trampoline+0x25/0x50 ? lock_acquired+0x392/0xbc0 ? _raw_spin_lock_irqsave+0x50/0x70 ? __get_valid_kprobe+0x1f0/0x1f0 ? _raw_spin_unlock_irqrestore+0x3b/0x40 ? finish_task_switch+0x4b9/0x6d0 ? __switch_to_asm+0x34/0x70 ? __switch_to_asm+0x40/0x70 The code within the kretprobe handler checks for probe reentrancy, so we won't trigger any _raw_spin_lock_irqsave probe in there. The problem is in outside kprobe_flush_task, where we call: kprobe_flush_task kretprobe_table_lock raw_spin_lock_irqsave _raw_spin_lock_irqsave where _raw_spin_lock_irqsave triggers the kretprobe and installs kretprobe_trampoline handler on _raw_spin_lock_irqsave return. The kretprobe_trampoline handler is then executed with already locked kretprobe_table_locks, and first thing it does is to lock kretprobe_table_locks ;-) the whole lockup path like: kprobe_flush_task kretprobe_table_lock raw_spin_lock_irqsave _raw_spin_lock_irqsave ---> probe triggered, kretprobe_trampoline installed ---> kretprobe_table_locks locked kretprobe_trampoline trampoline_handler kretprobe_hash_lock(current, &head, &flags); <--- deadlock Adding kprobe_busy_begin/end helpers that mark code with fake probe installed to prevent triggering of another kprobe within this code. Using these helpers in kprobe_flush_task, so the probe recursion protection check is hit and the probe is never set to prevent above lockup. Link: http://lkml.kernel.org/r/158927059835.27680.7011202830041561604.stgit@devnote2 Fixes: ef53d9c ("kprobes: improve kretprobe scalability with hashed locking") Cc: Ingo Molnar <mingo@kernel.org> Cc: "Gustavo A . R . Silva" <gustavoars@kernel.org> Cc: Anders Roxell <anders.roxell@linaro.org> Cc: "Naveen N . Rao" <naveen.n.rao@linux.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: stable@vger.kernel.org Reported-by: "Ziqian SUN (Zamir)" <zsun@redhat.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Commit 7e9f5e6 ("arm64: vdso: Add --eh-frame-hdr to ldflags") results in a .eh_frame_hdr section for the vDSO, which in turn causes the libgcc unwinder to unwind out of signal handlers using the .eh_frame information populated by our .cfi directives. In conjunction with a4eb355 ("arm64: vdso: Fix CFI directives in sigreturn trampoline"), this has been shown to cause segmentation faults originating from within the unwinder during thread cancellation: | Thread 14 "virtio-net-rx" received signal SIGSEGV, Segmentation fault. | 0x0000000000435e24 in uw_frame_state_for () | (gdb) bt | #0 0x0000000000435e24 in uw_frame_state_for () | #1 0x0000000000436e88 in _Unwind_ForcedUnwind_Phase2 () | #2 0x00000000004374d8 in _Unwind_ForcedUnwind () | #3 0x0000000000428400 in __pthread_unwind (buf=<optimized out>) at unwind.c:121 | #4 0x0000000000429808 in __do_cancel () at ./pthreadP.h:304 | #5 sigcancel_handler (sig=32, si=0xffff33c743f0, ctx=<optimized out>) at nptl-init.c:200 | thesofproject#6 sigcancel_handler (sig=<optimized out>, si=0xffff33c743f0, ctx=<optimized out>) at nptl-init.c:165 | thesofproject#7 <signal handler called> | thesofproject#8 futex_wait_cancelable (private=0, expected=0, futex_word=0x3890b708) at ../sysdeps/unix/sysv/linux/futex-internal.h:88 After considerable bashing of heads, it appears that our CFI directives for unwinding out of the sigreturn trampoline are only processed by libgcc when both a .eh_frame_hdr section is present *and* the mysterious NOP is covered by an entry in .eh_frame. With both of these now in place, it has highlighted that our CFI directives are not comprehensive enough to restore the stack pointer of the interrupted context. This results in libgcc falling back to an arm64-specific unwinder after computing a bogus PC value from the unwind tables. The unwinder promptly dereferences this bogus address in an attempt to see if the pointed-to instruction sequence looks like the sigreturn trampoline. Restore the old unwind behaviour, which relied solely on heuristics in the unwinder, by removing the .eh_frame_hdr section from the vDSO and commenting out the insufficient CFI directives for now. Add comments to explain the current, miserable state of affairs. Cc: Tamas Zsoldos <tamas.zsoldos@arm.com> Cc: Szabolcs Nagy <szabolcs.nagy@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Daniel Kiss <daniel.kiss@arm.com> Acked-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reported-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Will Deacon <will@kernel.org>

commit 9b38cc7 upstream. Ziqian reported lockup when adding retprobe on _raw_spin_lock_irqsave. My test was also able to trigger lockdep output: ============================================ WARNING: possible recursive locking detected 5.6.0-rc6+ thesofproject#6 Not tainted -------------------------------------------- sched-messaging/2767 is trying to acquire lock: ffffffff9a492798 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_hash_lock+0x52/0xa0 but task is already holding lock: ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(kretprobe_table_locks[i].lock)); lock(&(kretprobe_table_locks[i].lock)); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by sched-messaging/2767: #0: ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50 stack backtrace: CPU: 3 PID: 2767 Comm: sched-messaging Not tainted 5.6.0-rc6+ thesofproject#6 Call Trace: dump_stack+0x96/0xe0 __lock_acquire.cold.57+0x173/0x2b7 ? native_queued_spin_lock_slowpath+0x42b/0x9e0 ? lockdep_hardirqs_on+0x590/0x590 ? __lock_acquire+0xf63/0x4030 lock_acquire+0x15a/0x3d0 ? kretprobe_hash_lock+0x52/0xa0 _raw_spin_lock_irqsave+0x36/0x70 ? kretprobe_hash_lock+0x52/0xa0 kretprobe_hash_lock+0x52/0xa0 trampoline_handler+0xf8/0x940 ? kprobe_fault_handler+0x380/0x380 ? find_held_lock+0x3a/0x1c0 kretprobe_trampoline+0x25/0x50 ? lock_acquired+0x392/0xbc0 ? _raw_spin_lock_irqsave+0x50/0x70 ? __get_valid_kprobe+0x1f0/0x1f0 ? _raw_spin_unlock_irqrestore+0x3b/0x40 ? finish_task_switch+0x4b9/0x6d0 ? __switch_to_asm+0x34/0x70 ? __switch_to_asm+0x40/0x70 The code within the kretprobe handler checks for probe reentrancy, so we won't trigger any _raw_spin_lock_irqsave probe in there. The problem is in outside kprobe_flush_task, where we call: kprobe_flush_task kretprobe_table_lock raw_spin_lock_irqsave _raw_spin_lock_irqsave where _raw_spin_lock_irqsave triggers the kretprobe and installs kretprobe_trampoline handler on _raw_spin_lock_irqsave return. The kretprobe_trampoline handler is then executed with already locked kretprobe_table_locks, and first thing it does is to lock kretprobe_table_locks ;-) the whole lockup path like: kprobe_flush_task kretprobe_table_lock raw_spin_lock_irqsave _raw_spin_lock_irqsave ---> probe triggered, kretprobe_trampoline installed ---> kretprobe_table_locks locked kretprobe_trampoline trampoline_handler kretprobe_hash_lock(current, &head, &flags); <--- deadlock Adding kprobe_busy_begin/end helpers that mark code with fake probe installed to prevent triggering of another kprobe within this code. Using these helpers in kprobe_flush_task, so the probe recursion protection check is hit and the probe is never set to prevent above lockup. Link: http://lkml.kernel.org/r/158927059835.27680.7011202830041561604.stgit@devnote2 Fixes: ef53d9c ("kprobes: improve kretprobe scalability with hashed locking") Cc: Ingo Molnar <mingo@kernel.org> Cc: "Gustavo A . R . Silva" <gustavoars@kernel.org> Cc: Anders Roxell <anders.roxell@linaro.org> Cc: "Naveen N . Rao" <naveen.n.rao@linux.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: stable@vger.kernel.org Reported-by: "Ziqian SUN (Zamir)" <zsun@redhat.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

After entering kdb due to breakpoint, when we execute 'ss' or 'go' (will delay installing breakpoints, do single-step first), it won't work correctly, and it will enter kdb due to oops. It's because the reason gotten in kdb_stub() is not as expected, and it seems that the ex_vector for single-step should be 0, like what arch powerpc/sh/parisc has implemented. Before the patch: Entering kdb (current=0xffff8000119e2dc0, pid 0) on processor 0 due to Keyboard Entry [0]kdb> bp printk Instruction(i) BP #0 at 0xffff8000101486cc (printk) is enabled addr at ffff8000101486cc, hardtype=0 installed=0 [0]kdb> g / # echo h > /proc/sysrq-trigger Entering kdb (current=0xffff0000fa878040, pid 266) on processor 3 due to Breakpoint @ 0xffff8000101486cc [3]kdb> ss Entering kdb (current=0xffff0000fa878040, pid 266) on processor 3 Oops: (null) due to oops @ 0xffff800010082ab8 CPU: 3 PID: 266 Comm: sh Not tainted 5.7.0-rc4-13839-gf0e5ad491718 #6 Hardware name: linux,dummy-virt (DT) pstate: 00000085 (nzcv daIf -PAN -UAO) pc : el1_irq+0x78/0x180 lr : __handle_sysrq+0x80/0x190 sp : ffff800015003bf0 x29: ffff800015003d20 x28: ffff0000fa878040 x27: 0000000000000000 x26: ffff80001126b1f0 x25: ffff800011b6a0d8 x24: 0000000000000000 x23: 0000000080200005 x22: ffff8000101486cc x21: ffff800015003d30 x20: 0000ffffffffffff x19: ffff8000119f2000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000 x8 : ffff800015003e50 x7 : 0000000000000002 x6 : 00000000380b9990 x5 : ffff8000106e99e8 x4 : ffff0000fadd83c0 x3 : 0000ffffffffffff x2 : ffff800011b6a0d8 x1 : ffff800011b6a000 x0 : ffff80001130c9d8 Call trace: el1_irq+0x78/0x180 printk+0x0/0x84 write_sysrq_trigger+0xb0/0x118 proc_reg_write+0xb4/0xe0 __vfs_write+0x18/0x40 vfs_write+0xb0/0x1b8 ksys_write+0x64/0xf0 __arm64_sys_write+0x14/0x20 el0_svc_common.constprop.2+0xb0/0x168 do_el0_svc+0x20/0x98 el0_sync_handler+0xec/0x1a8 el0_sync+0x140/0x180 [3]kdb> After the patch: Entering kdb (current=0xffff8000119e2dc0, pid 0) on processor 0 due to Keyboard Entry [0]kdb> bp printk Instruction(i) BP #0 at 0xffff8000101486cc (printk) is enabled addr at ffff8000101486cc, hardtype=0 installed=0 [0]kdb> g / # echo h > /proc/sysrq-trigger Entering kdb (current=0xffff0000fa852bc0, pid 268) on processor 0 due to Breakpoint @ 0xffff8000101486cc [0]kdb> g Entering kdb (current=0xffff0000fa852bc0, pid 268) on processor 0 due to Breakpoint @ 0xffff8000101486cc [0]kdb> ss Entering kdb (current=0xffff0000fa852bc0, pid 268) on processor 0 due to SS trap @ 0xffff800010082ab8 [0]kdb> Fixes: 44679a4 ("arm64: KGDB: Add step debugging support") Signed-off-by: Wei Li <liwei391@huawei.com> Tested-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200509214159.19680-2-liwei391@huawei.com Signed-off-by: Will Deacon <will@kernel.org>

… set We received an error report that perf-record caused 'Segmentation fault' on a newly system (e.g. on the new installed ubuntu). (gdb) backtrace #0 __read_once_size (size=4, res=<synthetic pointer>, p=0x14) at /root/0-jinyao/acme/tools/include/linux/compiler.h:139 #1 atomic_read (v=0x14) at /root/0-jinyao/acme/tools/include/asm/../../arch/x86/include/asm/atomic.h:28 #2 refcount_read (r=0x14) at /root/0-jinyao/acme/tools/include/linux/refcount.h:65 #3 perf_mmap__read_init (map=map@entry=0x0) at mmap.c:177 #4 0x0000561ce5c0de39 in perf_evlist__poll_thread (arg=0x561ce68584d0) at util/sideband_evlist.c:62 #5 0x00007fad78491609 in start_thread (arg=<optimized out>) at pthread_create.c:477 #6 0x00007fad7823c103 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95 The root cause is, evlist__add_bpf_sb_event() just returns 0 if HAVE_LIBBPF_SUPPORT is not defined (inline function path). So it will not create a valid evsel for side-band event. But perf-record still creates BPF side band thread to process the side-band event, then the error happpens. We can reproduce this issue by removing the libelf-dev. e.g. 1. apt-get remove libelf-dev 2. perf record -a -- sleep 1 root@test:~# ./perf record -a -- sleep 1 perf: Segmentation fault Obtained 6 stack frames. ./perf(+0x28eee8) [0x5562d6ef6ee8] /lib/x86_64-linux-gnu/libc.so.6(+0x46210) [0x7fbfdc65f210] ./perf(+0x342e74) [0x5562d6faae74] ./perf(+0x257e39) [0x5562d6ebfe39] /lib/x86_64-linux-gnu/libpthread.so.0(+0x9609) [0x7fbfdc990609] /lib/x86_64-linux-gnu/libc.so.6(clone+0x43) [0x7fbfdc73b103] Segmentation fault (core dumped) To fix this issue, 1. We either install the missing libraries to let HAVE_LIBBPF_SUPPORT be defined. e.g. apt-get install libelf-dev and install other related libraries. 2. Use this patch to skip the side-band event setup if HAVE_LIBBPF_SUPPORT is not set. Committer notes: The side band thread is not used just with BPF, it is also used with --switch-output-event, so narrow the ifdef to the BPF specific part. Fixes: 23cbb41 ("perf record: Move side band evlist setup to separate routine") Signed-off-by: Jin Yao <yao.jin@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jin Yao <yao.jin@intel.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lore.kernel.org/lkml/20200805022937.29184-1-yao.jin@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

struct swap_info_struct si.flags could be accessed concurrently as noticed by KCSAN, BUG: KCSAN: data-race in scan_swap_map_slots / swap_readpage write to 0xffff9c77b80ac400 of 8 bytes by task 91325 on cpu 16: scan_swap_map_slots+0x6fe/0xb50 scan_swap_map_slots at mm/swapfile.c:887 get_swap_pages+0x39d/0x5c0 get_swap_page+0x377/0x524 add_to_swap+0xe4/0x1c0 shrink_page_list+0x1740/0x2820 shrink_inactive_list+0x316/0x8b0 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffff9c77b80ac400 of 8 bytes by task 5422 on cpu 7: swap_readpage+0x204/0x6a0 swap_readpage at mm/page_io.c:380 read_swap_cache_async+0xa2/0xb0 swapin_readahead+0x6a0/0x890 do_swap_page+0x465/0xeb0 __handle_mm_fault+0xc7a/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Reported by Kernel Concurrency Sanitizer on: CPU: 7 PID: 5422 Comm: gmain Tainted: G W O L 5.5.0-next-20200204+ #6 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 Other reads, read to 0xffff91ea33eac400 of 8 bytes by task 11276 on cpu 120: __swap_writepage+0x140/0xc20 __swap_writepage at mm/page_io.c:289 read to 0xffff91ea33eac400 of 8 bytes by task 11264 on cpu 16: swap_set_page_dirty+0x44/0x1f4 swap_set_page_dirty at mm/page_io.c:442 The write is under &si->lock, but the reads are done as lockless. Since the reads only check for a specific bit in the flag, it is harmless even if load tearing happens. Thus, just mark them as intentional data races using the data_race() macro. [cai@lca.pw: add a missing annotation] Link: http://lkml.kernel.org/r/1581612585-5812-1-git-send-email-cai@lca.pw Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Link: http://lkml.kernel.org/r/20200207003601.1526-1-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

swap_cache_info.* could be accessed concurrently as noticed by KCSAN, BUG: KCSAN: data-race in lookup_swap_cache / lookup_swap_cache write to 0xffffffff85517318 of 8 bytes by task 94138 on cpu 101: lookup_swap_cache+0x12e/0x460 lookup_swap_cache at mm/swap_state.c:322 do_swap_page+0x112/0xeb0 __handle_mm_fault+0xc7a/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffffffff85517318 of 8 bytes by task 91655 on cpu 100: lookup_swap_cache+0x117/0x460 lookup_swap_cache at mm/swap_state.c:322 shmem_swapin_page+0xc7/0x9e0 shmem_getpage_gfp+0x2ca/0x16c0 shmem_fault+0xef/0x3c0 __do_fault+0x9e/0x220 do_fault+0x4a0/0x920 __handle_mm_fault+0xc69/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Reported by Kernel Concurrency Sanitizer on: CPU: 100 PID: 91655 Comm: systemd-journal Tainted: G W O L 5.5.0-next-20200204+ #6 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 write to 0xffffffff8d717308 of 8 bytes by task 11365 on cpu 87: __delete_from_swap_cache+0x681/0x8b0 __delete_from_swap_cache at mm/swap_state.c:178 read to 0xffffffff8d717308 of 8 bytes by task 11275 on cpu 53: __delete_from_swap_cache+0x66e/0x8b0 __delete_from_swap_cache at mm/swap_state.c:178 Both the read and write are done as lockless. Since swap_cache_info.* are only used to print out counter information, even if any of them missed a few incremental due to data races, it will be harmless, so just mark it as an intentional data race using the data_race() macro. While at it, fix a checkpatch.pl warning, WARNING: Single statement macros should not use a do {} while (0) loop Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Link: http://lkml.kernel.org/r/20200207003715.1578-1-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

struct mem_cgroup_per_node mz.lru_zone_size[zone_idx][lru] could be accessed concurrently as noticed by KCSAN, BUG: KCSAN: data-race in lruvec_lru_size / mem_cgroup_update_lru_size write to 0xffff9c804ca285f8 of 8 bytes by task 50951 on cpu 12: mem_cgroup_update_lru_size+0x11c/0x1d0 mem_cgroup_update_lru_size at mm/memcontrol.c:1266 isolate_lru_pages+0x6a9/0xf30 shrink_active_list+0x123/0xcc0 shrink_lruvec+0x8fd/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffff9c804ca285f8 of 8 bytes by task 50964 on cpu 95: lruvec_lru_size+0xbb/0x270 mem_cgroup_get_zone_lru_size at include/linux/memcontrol.h:536 (inlined by) lruvec_lru_size at mm/vmscan.c:326 shrink_lruvec+0x1d0/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_current+0xa6/0x120 alloc_slab_page+0x3b1/0x540 allocate_slab+0x70/0x660 new_slab+0x46/0x70 ___slab_alloc+0x4ad/0x7d0 __slab_alloc+0x43/0x70 kmem_cache_alloc+0x2c3/0x420 getname_flags+0x4c/0x230 getname+0x22/0x30 do_sys_openat2+0x205/0x3b0 do_sys_open+0x9a/0xf0 __x64_sys_openat+0x62/0x80 do_syscall_64+0x91/0xb47 entry_SYSCALL_64_after_hwframe+0x49/0xbe Reported by Kernel Concurrency Sanitizer on: CPU: 95 PID: 50964 Comm: cc1 Tainted: G W O L 5.5.0-next-20200204+ #6 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 The write is under lru_lock, but the read is done as lockless. The scan count is used to determine how aggressively the anon and file LRU lists should be scanned. Load tearing could generate an inefficient heuristic, so fix it by adding READ_ONCE() for the read. Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Link: http://lkml.kernel.org/r/20200206034945.2481-1-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Read to lru_add_pvec->nr could be interrupted and then write to the same variable. The write has local interrupt disabled, but the plain reads result in data races. However, it is unlikely the compilers could do much damage here given that lru_add_pvec->nr is a "unsigned char" and there is an existing compiler barrier. Thus, annotate the reads using the data_race() macro. The data races were reported by KCSAN, BUG: KCSAN: data-race in lru_add_drain_cpu / rotate_reclaimable_page write to 0xffff9291ebcb8a40 of 1 bytes by interrupt on cpu 23: rotate_reclaimable_page+0x2df/0x490 pagevec_add at include/linux/pagevec.h:81 (inlined by) rotate_reclaimable_page at mm/swap.c:259 end_page_writeback+0x1b5/0x2b0 end_swap_bio_write+0x1d0/0x280 bio_endio+0x297/0x560 dec_pending+0x218/0x430 [dm_mod] clone_endio+0xe4/0x2c0 [dm_mod] bio_endio+0x297/0x560 blk_update_request+0x201/0x920 scsi_end_request+0x6b/0x4a0 scsi_io_completion+0xb7/0x7e0 scsi_finish_command+0x1ed/0x2a0 scsi_softirq_done+0x1c9/0x1d0 blk_done_softirq+0x181/0x1d0 __do_softirq+0xd9/0x57c irq_exit+0xa2/0xc0 do_IRQ+0x8b/0x190 ret_from_intr+0x0/0x42 delay_tsc+0x46/0x80 __const_udelay+0x3c/0x40 __udelay+0x10/0x20 kcsan_setup_watchpoint+0x202/0x3a0 __tsan_read1+0xc2/0x100 lru_add_drain_cpu+0xb8/0x3f0 lru_add_drain+0x25/0x40 shrink_active_list+0xe1/0xc80 shrink_lruvec+0x766/0xb70 shrink_node+0x2d6/0xca0 do_try_to_free_pages+0x1f7/0x9a0 try_to_free_pages+0x252/0x5b0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x16e/0x6f0 __handle_mm_fault+0xcd5/0xd40 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffff9291ebcb8a40 of 1 bytes by task 37761 on cpu 23: lru_add_drain_cpu+0xb8/0x3f0 lru_add_drain_cpu at mm/swap.c:602 lru_add_drain+0x25/0x40 shrink_active_list+0xe1/0xc80 shrink_lruvec+0x766/0xb70 shrink_node+0x2d6/0xca0 do_try_to_free_pages+0x1f7/0x9a0 try_to_free_pages+0x252/0x5b0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x16e/0x6f0 __handle_mm_fault+0xcd5/0xd40 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 2 locks held by oom02/37761: #0: ffff9281e5928808 (&mm->mmap_sem#2){++++}, at: do_page_fault #1: ffffffffb3ade380 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part irq event stamp: 1949217 trace_hardirqs_on_thunk+0x1a/0x1c __do_softirq+0x2e7/0x57c __do_softirq+0x34c/0x57c irq_exit+0xa2/0xc0 Reported by Kernel Concurrency Sanitizer on: CPU: 23 PID: 37761 Comm: oom02 Not tainted 5.6.0-rc3-next-20200226+ #6 Hardware name: HP ProLiant BL660c Gen9, BIOS I38 10/17/2018 Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Marco Elver <elver@google.com> Link: http://lkml.kernel.org/r/20200228044018.1263-1-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

BUG: KCSAN: data-race in page_cpupid_xchg_last / put_page write (marked) to 0xfffffc0d48ec1a00 of 8 bytes by task 91442 on cpu 3: page_cpupid_xchg_last+0x51/0x80 page_cpupid_xchg_last at mm/mmzone.c:109 (discriminator 11) wp_page_reuse+0x3e/0xc0 wp_page_reuse at mm/memory.c:2453 do_wp_page+0x472/0x7b0 do_wp_page at mm/memory.c:2798 __handle_mm_fault+0xcb0/0xd00 handle_pte_fault at mm/memory.c:4049 (inlined by) __handle_mm_fault at mm/memory.c:4163 handle_mm_fault+0xfc/0x2f0 handle_mm_fault at mm/memory.c:4200 do_page_fault+0x263/0x6f9 do_user_addr_fault at arch/x86/mm/fault.c:1465 (inlined by) do_page_fault at arch/x86/mm/fault.c:1539 page_fault+0x34/0x40 read to 0xfffffc0d48ec1a00 of 8 bytes by task 94817 on cpu 69: put_page+0x15a/0x1f0 page_zonenum at include/linux/mm.h:923 (inlined by) is_zone_device_page at include/linux/mm.h:929 (inlined by) page_is_devmap_managed at include/linux/mm.h:948 (inlined by) put_page at include/linux/mm.h:1023 wp_page_copy+0x571/0x930 wp_page_copy at mm/memory.c:2615 do_wp_page+0x107/0x7b0 __handle_mm_fault+0xcb0/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Reported by Kernel Concurrency Sanitizer on: CPU: 69 PID: 94817 Comm: systemd-udevd Tainted: G W O L 5.5.0-next-20200204+ #6 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 A page never changes its zone number. The zone number happens to be stored in the same word as other bits which are modified, but the zone number bits will never be modified by any other write, so it can accept a reload of the zone bits after an intervening write and it don't need to use READ_ONCE(). Thus, annotate this data race using ASSERT_EXCLUSIVE_BITS() to also assert that there are no concurrent writes to it. Suggested-by: Marco Elver <elver@google.com> Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Link: http://lkml.kernel.org/r/1581619089-14472-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In our production system, we observed rcu stalls when 'bpftool prog` is running. rcu: INFO: rcu_sched self-detected stall on CPU rcu: \x097-....: (20999 ticks this GP) idle=302/1/0x4000000000000000 softirq=1508852/1508852 fqs=4913 \x09(t=21031 jiffies g=2534773 q=179750) NMI backtrace for cpu 7 CPU: 7 PID: 184195 Comm: bpftool Kdump: loaded Tainted: G W 5.8.0-00004-g68bfc7f8c1b4 #6 Hardware name: Quanta Twin Lakes MP/Twin Lakes Passive MP, BIOS F09_3A17 05/03/2019 Call Trace: <IRQ> dump_stack+0x57/0x70 nmi_cpu_backtrace.cold+0x14/0x53 ? lapic_can_unplug_cpu.cold+0x39/0x39 nmi_trigger_cpumask_backtrace+0xb7/0xc7 rcu_dump_cpu_stacks+0xa2/0xd0 rcu_sched_clock_irq.cold+0x1ff/0x3d9 ? tick_nohz_handler+0x100/0x100 update_process_times+0x5b/0x90 tick_sched_timer+0x5e/0xf0 __hrtimer_run_queues+0x12a/0x2a0 hrtimer_interrupt+0x10e/0x280 __sysvec_apic_timer_interrupt+0x51/0xe0 asm_call_on_stack+0xf/0x20 </IRQ> sysvec_apic_timer_interrupt+0x6f/0x80 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:task_file_seq_get_next+0x71/0x220 Code: 00 00 8b 53 1c 49 8b 7d 00 89 d6 48 8b 47 20 44 8b 18 41 39 d3 76 75 48 8b 4f 20 8b 01 39 d0 76 61 41 89 d1 49 39 c1 48 19 c0 <48> 8b 49 08 21 d0 48 8d 04 c1 4c 8b 08 4d 85 c9 74 46 49 8b 41 38 RSP: 0018:ffffc90006223e10 EFLAGS: 00000297 RAX: ffffffffffffffff RBX: ffff888f0d172388 RCX: ffff888c8c07c1c0 RDX: 00000000000f017b RSI: 00000000000f017b RDI: ffff888c254702c0 RBP: ffffc90006223e68 R08: ffff888be2a1c140 R09: 00000000000f017b R10: 0000000000000002 R11: 0000000000100000 R12: ffff888f23c24118 R13: ffffc90006223e60 R14: ffffffff828509a0 R15: 00000000ffffffff task_file_seq_next+0x52/0xa0 bpf_seq_read+0xb9/0x320 vfs_read+0x9d/0x180 ksys_read+0x5f/0xe0 do_syscall_64+0x38/0x60 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f8815f4f76e Code: c0 e9 f6 fe ff ff 55 48 8d 3d 76 70 0a 00 48 89 e5 e8 36 06 02 00 66 0f 1f 44 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 52 c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 RSP: 002b:00007fff8f9df578 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 000000000170b9c0 RCX: 00007f8815f4f76e RDX: 0000000000001000 RSI: 00007fff8f9df5b0 RDI: 0000000000000007 RBP: 00007fff8f9e05f0 R08: 0000000000000049 R09: 0000000000000010 R10: 00007f881601fa40 R11: 0000000000000246 R12: 00007fff8f9e05a8 R13: 00007fff8f9e05a8 R14: 0000000001917f90 R15: 000000000000e22e Note that `bpftool prog` actually calls a task_file bpf iterator program to establish an association between prog/map/link/btf anon files and processes. In the case where the above rcu stall occured, we had a process having 1587 tasks and each task having roughly 81305 files. This implied 129 million bpf prog invocations. Unfortunwtely none of these files are prog/map/link/btf files so bpf iterator/prog needs to traverse all these files and not able to return to user space since there are no seq_file buffer overflow. This patch fixed the issue in bpf_seq_read() to limit the number of visited objects. If the maximum number of visited objects is reached, no more objects will be visited in the current syscall. If there is nothing written in the seq_file buffer, -EAGAIN will return to the user so user can try again. The maximum number of visited objects is set at 1 million. In our Intel Xeon D-2191 2.3GHZ 18-core server, bpf_seq_read() visiting 1 million files takes around 0.18 seconds. We did not use cond_resched() since for some iterators, e.g., netlink iterator, where rcu read_lock critical section spans between consecutive seq_ops->next(), which makes impossible to do cond_resched() in the key while loop of function bpf_seq_read(). Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: Paul E. McKenney <paulmck@kernel.org> Link: https://lore.kernel.org/bpf/20200818222309.2181348-1-yhs@fb.com

I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>

ranj063 added 6 commits June 25, 2018 13:18

ASoC: pcm: add methods to create/remove virtual dai link

771505c

This patch adds the methods for create a virtual FE dal link and add it to the sound card. It also adds the method to free the virtual FE connected to the card. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

ASoC: pcm: do no register pcm device for virtual FE dai links

481f66d

Virtual FE dai links do not need to register the pcm device. So just create the empty pcm device and substream in the requested direction. Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

ranj063 closed this Jun 25, 2018

paulstelian97 mentioned this pull request Oct 12, 2021

Dell Latitude 9520: No Audio #3206

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lucastanure mentioned this pull request May 2, 2022

Missing SSP2 (I2S) from Up Xtreme WHL-I5 #3624

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ejmarkow mentioned this pull request Jul 31, 2022

[BUG] NO SOUND for GeminiLake with ES8336 #3336

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wisbit mentioned this pull request Sep 2, 2022

No sound at all - TECLAST F15 PLUS - Intel Corporation Celeron/Pentium Silver Processor High Definition Audio #3842

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aplitvinov mentioned this pull request Apr 21, 2023

No sound on Huawei Matebook 14 (2021) - even on Linux 6.2 #4305

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Introducing Virtual FE dai link #6

Introducing Virtual FE dai link #6
ranj063 wants to merge 6 commits intothesofproject:topic/sof-devfrom
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ranj063 commented Jun 25, 2018

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