[Bug]: iOS TestFlight build 58 crashes with SIGSEGV in a stack guard region

Before submitting

Searched existing issues; no matching crash signature found.
Included crash diagnostics for investigation.

Area

apps/mobile, native iOS app

Steps to reproduce

Not available in the supplied diagnostic report. The report records one crash at 2026-10-09 01:33:27; it does not identify the screen, preceding action, or a timezone. Reproducibility and frequency are unknown.

Expected behavior

The mobile app should remain running without a native crash.

Actual behavior

T3 Code's native iOS app terminated with signal 11. The diagnostic reports Namespace SIGNAL, Code 0xb, exception type 1, and exception code 2. The fault address 0x16ba97ef8 falls inside a Stack Guard region.

The attributed stack begins in libswiftCore.dylib, with repeated Swift runtime frames followed by T3Code, SwiftUI, SwiftUICore, and AttributeGraph frames. This is consistent with a possible stack overflow, but the root cause is unconfirmed. Symbolication with the matching build 58 dSYM is needed to identify the app functions involved.

Impact

The app process terminates. The supplied report does not establish whether this happens repeatedly or whether work is lost.

Version or commit

App version 0.1.0, build 58, distributed through TestFlight.

Environment

OS: iPhone OS 27.0 (24A435)
Device identifier: iPhone17,1
Architecture: arm64e
Bundle identifier: com.t3tools.t3code.swiftui
Low Power Mode: enabled
Region: IN

Logs or stack traces

Metadata below is copied from the supplied pasted-text.txt. Stack entries retain the diagnostic's order and binary offsets; they are not symbolicated function names.

{
  "platformArchitecture": "arm64e",
  "terminationReason": "Namespace SIGNAL, Code 0xb",
  "exceptionType": 1,
  "appBuildVersion": "58",
  "isTestFlightApp": true,
  "osVersion": "iPhone OS 27.0 (24A435)",
  "bundleIdentifier": "com.t3tools.t3code.swiftui",
  "deviceType": "iPhone17,1",
  "exceptionCode": 2,
  "virtualMemoryRegionInfo": "0x16ba97ef8 is in 0x16ba94000-0x16ba98000;  bytes after start: 16120  bytes before end: 263\n      REGION TYPE                   START - END        [ VSIZE] PRT/MAX SHRMOD  REGION DETAIL\n      Malloc Small               11cc00000-11d000000   [ 4096K] rw-/rwx SM=PRV  \n      GAP OF 0x4ea94000 BYTES\n--->  Stack Guard                16ba94000-16ba98000   [   16K] ---/rwx SM=PRV  \n      Stack                      16ba98000-16bb94000   [ 1008K] rw-/rwx SM=COW  ",
  "signal": 11,
  "regionFormat": "IN",
  "appVersion": "0.1.0",
  "pid": 68726,
  "lowPowerModeEnabled": true
}

Complete attributed thread stack, 104 frames

#  Binary                         Offset (decimal)  Address
00 libswiftCore.dylib                 268912  0x1a1133a70
01 libswiftCore.dylib                 264448  0x1a1132900
02 libswiftCore.dylib                1987540  0x1a12d73d4
03 libswiftCore.dylib                1976144  0x1a12d4750
04 libswiftCore.dylib                 301664  0x1a113ba60
05 libswiftCore.dylib                 294872  0x1a1139fd8
06 libswiftCore.dylib                1954540  0x1a12cf2ec
07 libswiftCore.dylib                 291088  0x1a1139110
08 libswiftCore.dylib                1931928  0x1a12c9a98
09 libswiftCore.dylib                 291088  0x1a1139110
10 libswiftCore.dylib                1931928  0x1a12c9a98
11 libswiftCore.dylib                 291088  0x1a1139110
12 libswiftCore.dylib                1931928  0x1a12c9a98
13 libswiftCore.dylib                 291088  0x1a1139110
14 libswiftCore.dylib                1931928  0x1a12c9a98
15 libswiftCore.dylib                 265264  0x1a1132c30
16 libswiftCore.dylib                 341300  0x1a1145534
17 T3Code                              16660  0x104270114
18 T3Code                            7288952  0x10495f878
19 SwiftUI                            447936  0x1a9d785c0
20 T3Code                            7274952  0x10495c1c8
21 SwiftUI                          14720032  0x1aab14c20
22 T3Code                            7266804  0x10495a1f4
23 SwiftUI                            447936  0x1a9d785c0
24 T3Code                            7206364  0x10494b5dc
25 T3Code                            7799744  0x1049dc3c0
26 SwiftUI                           1691660  0x1a9ea800c
27 T3Code                            7202496  0x10494a6c0
28 SwiftUI                           1685716  0x1a9ea68d4
29 T3Code                            7157908  0x10493f894
30 T3Code                            7136836  0x10493a644
31 T3Code                            7104632  0x104932878
32 T3Code                            7101188  0x104931b04
33 T3Code                            7208904  0x10494bfc8
34 SwiftUICore                        302308  0x1a789dce4
35 SwiftUICore                        256036  0x1a7892824
36 SwiftUICore                        256108  0x1a789286c
37 SwiftUICore                        123608  0x1a78722d8
38 SwiftUICore                         85332  0x1a7868d54
39 SwiftUICore                         83604  0x1a7868694
40 AttributeGraph                      43352  0x1a9ccf958
41 AttributeGraph                      47436  0x1a9cd094c
42 AttributeGraph                      56100  0x1a9cd2b24
43 AttributeGraph                      15724  0x1a9cc8d6c
44 SwiftUICore                        286408  0x1a7899ec8
45 SwiftUICore                         83604  0x1a7868694
46 AttributeGraph                      43352  0x1a9ccf958
47 AttributeGraph                      47436  0x1a9cd094c
48 AttributeGraph                      56100  0x1a9cd2b24
49 AttributeGraph                      15724  0x1a9cc8d6c
50 SwiftUICore                        570860  0x1a78df5ec
51 AttributeGraph                      43352  0x1a9ccf958
52 AttributeGraph                      47436  0x1a9cd094c
53 AttributeGraph                      56100  0x1a9cd2b24
54 AttributeGraph                      15724  0x1a9cc8d6c
55 SwiftUICore                        284996  0x1a7899944
56 SwiftUICore                        288028  0x1a789a51c
57 SwiftUICore                         83604  0x1a7868694
58 AttributeGraph                      43352  0x1a9ccf958
59 AttributeGraph                      47436  0x1a9cd094c
60 AttributeGraph                      56100  0x1a9cd2b24
61 AttributeGraph                      15724  0x1a9cc8d6c
62 SwiftUICore                        284996  0x1a7899944
63 SwiftUICore                        288028  0x1a789a51c
64 SwiftUICore                         83604  0x1a7868694
65 AttributeGraph                      43352  0x1a9ccf958
66 AttributeGraph                      47436  0x1a9cd094c
67 AttributeGraph                      17156  0x1a9cc9304
68 AttributeGraph                      48468  0x1a9cd0d54
69 SwiftUICore                        649588  0x1a78f2974
70 SwiftUICore                        158712  0x1a787abf8
71 SwiftUICore                         79820  0x1a78677cc
72 SwiftUICore                        160892  0x1a787b47c
73 UIKitCore                         1123916  0x1a3dbc64c
74 SwiftUI                            117864  0x1a9d27c68
75 SwiftUI                            117700  0x1a9d27bc4
76 UIKitCore                           46580  0x1a3cb55f4
77 UIKitCore                           44584  0x1a3cb4e28
78 UIKitCore                           38712  0x1a3cb3738
79 QuartzCore                          62900  0x1a38465b4
80 QuartzCore                          60368  0x1a3845bd0
81 QuartzCore                          59272  0x1a3845788
82 QuartzCore                         138908  0x1a3858e9c
83 QuartzCore                         123848  0x1a38553c8
84 QuartzCore                         120768  0x1a38547c0
85 QuartzCore                         122904  0x1a3855018
86 QuartzCore                         120256  0x1a38545c0
87 UIKitCore                          407552  0x1a3d0d800
88 UIKitCore                          405108  0x1a3d0ce74
89 UIKitCore                          433032  0x1a3d13b88
90 UIKitCore                          432424  0x1a3d13928
91 UpdateCycle                          3008  0x2d272cbc0
92 CoreFoundation                     157644  0x19fa717cc
93 CoreFoundation                     303692  0x19fa9524c
94 CoreFoundation                     304220  0x19fa9545c
95 CoreFoundation                     239156  0x19fa85634
96 CoreFoundation                     243700  0x19fa867f4
97 GraphicsServices                     3876  0x24a148f24
98 UIKitCore                          762316  0x1a3d641cc
99 SwiftUI                            295940  0x1a9d53404
100 SwiftUI                            269136  0x1a9d4cb50
101 SwiftUI                            268816  0x1a9d4ca10
102 T3Code                            2640580  0x1044f0ac4
103 dyld                                21944  0x19f8d75b8

Binary UUIDs for symbolication:

{
  "libswiftCore.dylib": "D65D98D2-5161-3FA0-9B03-7B7085A01DAC",
  "T3Code": "0F35844F-4DF4-3C0B-9219-BD93D36DD502",
  "SwiftUI": "1D2A8243-1E78-3E43-AF2A-428BECD7EDD3",
  "SwiftUICore": "B3B15F84-D0FE-34BF-93C6-A9D22F4B750B",
  "AttributeGraph": "DF44FFFE-425B-3CB0-961F-351B2FC3F738",
  "UIKitCore": "AAC84A00-13AB-3B06-B622-A4E676971EB8",
  "QuartzCore": "76CE2A6E-DBA4-335D-A5AC-77A1C1B286A6",
  "UpdateCycle": "2FC1A9E2-8ADE-3559-A13F-0DD8E4DC6E74",
  "CoreFoundation": "9426FC9A-B36C-3096-B836-D17D6744A75B",
  "GraphicsServices": "D0170165-A973-3DBB-86EA-8EB7D0EA9ACB",
  "dyld": "D3F59B02-EE07-371B-B091-3F150A078ED8"
}

Supporting evidence

Source: user-supplied pasted-text.txt, an iOS crash diagnostic payload. The payload contains one crash diagnostic and nine thread entries. This issue includes the metadata and the complete attributed thread stack; it does not include the entire raw payload.

Workaround

No workaround was provided.

Additional reproduction details and an observed workaround from an affected user:

Native Swift phone app, version 0.1.0 (58), connected successfully to a Mac server through Direct over Tailscale.
Attempting to open existing threads repeatedly crashed the phone app.
Workaround observed: typing/sending a message to a different, randomly chosen thread, instead of trying to open the current threads, broke the crash cycle. This is one user observation; it has not been established as a reliable workaround for every affected device or a permanent fix.

We checked two crash reports retrieved directly from the paired iPhone before adding this here. Both reports have:

iPhone OS 27.0 (24A437).
App binary UUID 0F35844F-4DF4-3C0B-9219-BD93D36DD502, matching the binary in this issue.
Main-thread EXC_BAD_ACCESS / SIGSEGV, KERN_PROTECTION_FAILURE, with the fault address in a Stack Guard region.
99 recorded frames, of which 90 match the issue's 104-frame stack in order, comparing binary names and image offsets. This includes a contiguous 73-frame match through SwiftUI menu/section/toolbar construction and the following view-update path.
Twelve shared T3Code image offsets: 16660, 7274952, 7266804, 7206364, 7799744, 7202496, 7157908, 7136836, 7104632, 7101188, 7208904, 2640580.

The two local reports share the same crashing-thread path; a CoreFoundation frame differs between them. Their stacks are not identical to the original report: the upper Swift runtime/app frames differ. The evidence strongly supports the same crash signature/path, but the underlying cause remains unconfirmed without symbolication using the matching dSYM.

Raw crash reports are retained locally; no device identifiers, private hostnames, pairing credentials, thread contents, or raw diagnostic files are included in this comment.

Update from the affected device: no recurrence since build 58.

Now on T3 Code SwiftUI 0.1.0 (62), com.t3tools.t3code.swiftui, iPhone 16 Pro Max, iOS 27.0; desktop host 0.1.2-nightly.20261021.3499 (Windows 11).
The only SwiftUI crash reports on the phone are the two build 58 crashes from 9 Oct (opening existing threads over Direct/Tailscale, as described above). There are no crash reports from builds 60 or 62, although the app has been in regular use on both: iOS resource reports from builds 60 and 62 confirm activity up to 21 Oct.
I haven't seen the crash when opening threads since. That fits the toolbar stack fix in 7a4a9ef / build 60, though it's not proof.

Full build 58 .ips reports, including usedImages (Binary Images): https://gist.github.com/gmelvill/4b2766f0b0657bb41e198af89c868093

T3Code-2026-10-09-134712.ips and T3Code-2026-10-09-134908.ips, slice UUID 0f35844f-4df4-3c0b-9219-bd93d36dd502, build 58.
Redacted: store cohort/install tracking IDs, deviceIdentifierForVendor, incident and boot-session IDs, log-writing signature, device trial/rollout IDs and app container folder IDs. Threads, frames, image UUIDs/offsets, the exception and the VM region info are unchanged. The body is pretty-printed JSON, otherwise as retrieved from the device.

These still need the build 58 dSYM to symbolicate. If they confirm the same path as the 7a4a9ef fix, this looks fine to close as fixed in build 60.

what happened to all the testflight builds btw? they're gone since like a week, no updates, nightlies, anything and the app from the app store crashes literally within 2-5 minutes of use, sometimes, immediately, without any crash log, perhaps an OOM. But still, the mobile app is next to unusable, you have to type your message fast and send before it crashes again.

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[Bug]: iOS TestFlight build 58 crashes with SIGSEGV in a stack guard region #17297

Before submitting

Area

Steps to reproduce

Expected behavior

Actual behavior

Impact

Version or commit

Environment

Logs or stack traces

Supporting evidence

Workaround

Metadata

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[Bug]: iOS TestFlight build 58 crashes with SIGSEGV in a stack guard region #17297

Description

Before submitting

Area

Steps to reproduce

Expected behavior

Actual behavior

Impact

Version or commit

Environment

Logs or stack traces

Supporting evidence

Workaround

Activity

gmelvill commented on Oct 9, 2026

gmelvill commented on Oct 22, 2026

christhomas commented on Oct 25, 2026

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