Back in 2012 kurt@ added an abort call for the undefined behaviour cases on pthread_mutex_unlock. This helped me a great deal in examining the cause of some weird behaviour in icinga (or in the case of openbsd, just plain crash).
For shits and giggles I deceided to look into pthread_spin_unlock and saw that we return EPERM here, while POSIX states that this behaviour is unconditionally undefined.[0] Is there a reason why we shouldn't abort here as well? I don't have a particular usecase for this, but the mutex case helped me and it only seems like the right thing to do from a semetrical point of view. The only cases of pthread_spin_unlock in base I found were in libunbound (which with my testing with unwind didn't caused any issues) and gnu/llvm/compiler-rt/lib/tsan, which I don't know where to test. I have no idea which ports use it. martijn@ [0] https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_spin_unlock.html Index: librthread/rthread_spin_lock.c =================================================================== RCS file: /cvs/src/lib/librthread/rthread_spin_lock.c,v retrieving revision 1.5 diff -u -p -r1.5 rthread_spin_lock.c --- librthread/rthread_spin_lock.c 6 Apr 2020 00:01:08 -0000 1.5 +++ librthread/rthread_spin_lock.c 3 Oct 2020 09:42:21 -0000 @@ -102,12 +102,12 @@ pthread_spin_unlock(pthread_spinlock_t * pthread_spinlock_t l; if (lock == NULL || *lock == NULL) - return (EINVAL); + abort(); l = *lock; if (l->owner != self) - return (EPERM); + abort(); l->owner = NULL; _spinunlock(&l->lock); Index: libpthread/man/pthread_spin_unlock.3 =================================================================== RCS file: /cvs/src/lib/libpthread/man/pthread_spin_unlock.3,v retrieving revision 1.3 diff -u -p -r1.3 pthread_spin_unlock.3 --- libpthread/man/pthread_spin_unlock.3 6 Apr 2020 00:01:08 -0000 1.3 +++ libpthread/man/pthread_spin_unlock.3 3 Oct 2020 09:42:21 -0000 @@ -38,17 +38,14 @@ functions. .Sh RETURN VALUES If successful, .Fn pthread_spin_unlock -returns zero; otherwise an error number is returned to indicate the error. +returns zero. .Sh ERRORS .Fn pthread_spin_unlock -will fail if: -.Bl -tag -width Er -.It Bq Er EINVAL -The value specified by +will call +.Xr abort 3 +if the value specified by .Fa lock -is invalid. -.It Bq Er EPERM -The lock is not owned by the calling thread. +is invalid or if the lock is not owned by the calling thread. .El .Sh SEE ALSO .Xr pthread_spin_init 3 ,
