mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-06-05 12:12:28 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Fix ordering of pthread_create(pthread_t *thread)

Browse source 
This change fixes a bug where signal_latency_async_test would flake less
than 1/1000 of the time. What was happening was pthread_kill(sender_thr)
would return EFAULT. This was because pthread_create() was not returning
the thread object pointer until after clone() had been called. So it was
actually possible for the main thread to stall after calling clone() and
during that time the receiver would launch and receive a signal from the
sender thread, and then fail when it tried to send a pong. I thought I'd
use a barrier at first, in the test, to synchronize thread creation, but
I firmly believe that pthread_create() was to blame and now that's fixed
This commit is contained in:
Justine Tunney 2025-01-03 17:28:39 -08:00
parent ed6d133a27
commit e939659b70
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
6 changed files with 57 additions and 63 deletions
Download patch file Download diff file Expand all files Collapse all files

2
libc/thread/posixthread.internal.h
View file

@ -128,7 +128,7 @@ forceinline pureconst struct PosixThread *_pthread_self(void) {
}
forceinline void _pthread_ref(struct PosixThread *pt) {
atomic_fetch_add_explicit(&pt->pt_refs, 1, memory_order_acq_rel);
atomic_fetch_add_explicit(&pt->pt_refs, 1, memory_order_relaxed);
}
forceinline void _pthread_unref(struct PosixThread *pt) {