Skip to content

Relax memory ordering used in SameMutexCheck #96619

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
merged 3 commits into from May 5, 2022
Merged

Relax memory ordering used in SameMutexCheck #96619

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
df4457e
Relax memory ordering used in SameMutexCheck
May 1, 2022
a05df2e
Fix formatting
May 2, 2022
55a7d18
Add comment
May 2, 2022
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
10 changes: 8 additions & 2 deletions library/std/src/sys_common/condvar/check.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -24,8 +24,14 @@ impl SameMutexCheck {
}
pub fn verify(&self, mutex: &MovableMutex) {
let addr = mutex.raw() as *const imp::Mutex as *const () as *mut _;
match self.addr.compare_exchange(ptr::null_mut(), addr, Ordering::SeqCst, Ordering::SeqCst)
{
// Relaxed is okay here because we never read through `self.addr`, and only use it to
// compare addresses.
match self.addr.compare_exchange(
ptr::null_mut(),
addr,
Ordering::Relaxed,
Ordering::Relaxed,
) {
Ok(_) => {} // Stored the address
Err(n) if n == addr => {} // Lost a race to store the same address
_ => panic!("attempted to use a condition variable with two mutexes"),
Expand Down