Skip to content

Panic/return false on overflow in no_threads read/try_read impl #154526

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
rust-bors merged 2 commits into from
Apr 4, 2026
Merged

Panic/return false on overflow in no_threads read/try_read impl #154526

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
4b0caec
Panic/return false on overflow in no_threads read/try_read impl
asder8215 Mar 28, 2026
1d7d435
Panic on unlocking a non-read locked RwLock + provided better error msgs
asder8215 Mar 30, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 10 additions & 4 deletions library/std/src/sys/sync/rwlock/no_threads.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@ impl RwLock {
pub fn read(&self) {
let m = self.mode.get();
if m >= 0 {
self.mode.set(m + 1);
self.mode.set(m.checked_add(1).expect("rwlock overflowed read locks"));
} else {
rtabort!("rwlock locked for writing");
}
Expand All @@ -28,6 +28,9 @@ impl RwLock {
pub fn try_read(&self) -> bool {
let m = self.mode.get();
if m >= 0 {
if m == isize::MAX {
return false;
}
self.mode.set(m + 1);
true
} else {
Expand Down Expand Up @@ -56,16 +59,19 @@ impl RwLock {

#[inline]
pub unsafe fn read_unlock(&self) {
self.mode.set(self.mode.get() - 1);
assert!(
self.mode.replace(self.mode.get() - 1) > 0,
"rwlock has not been locked for reading"
);
}

#[inline]
pub unsafe fn write_unlock(&self) {
assert_eq!(self.mode.replace(0), -1);
assert_eq!(self.mode.replace(0), -1, "rwlock has not been locked for writing");
}

#[inline]
pub unsafe fn downgrade(&self) {
assert_eq!(self.mode.replace(1), -1);
assert_eq!(self.mode.replace(1), -1, "rwlock has not been locked for writing");
}
}
Loading