> Date: Tue, 15 Dec 2020 12:15:30 -0300
> From: Martin Pieuchot <m...@openbsd.org>
>
> When the first thread of multimedia/mpv exits after having played a video
> with the "gpu" (default) output, the programs receives a SIGSEV when it
> tries to execute one of its destructor:
>
> void
> _rthread_tls_destructors(pthread_t thread)
> {
> [...]
> for (i = 0; i < PTHREAD_DESTRUCTOR_ITERATIONS; i++) {
> for (rs = thread->local_storage; rs; rs = rs->next) {
> if (!rs->data)
> continue;
> if (rkeys[rs->keyid].destructor) {
> void (*destructor)(void *) =
> rkeys[rs->keyid].destructor;
> void *data = rs->data;
> rs->data = NULL;
> _spinunlock(&rkeyslock);
> destructor(data); <-- HERE
> _spinlock(&rkeyslock);
> }
> }
> }
> [...]
> }
>
> This doesn't happen with other outputs and I haven't checked/don't know
> which piece of code in the "gpu" output calls pthread_key_create().
>
> Full backtrace below.
>
> $ mpv *.mp4
> (+) Video --vid=1 (*) (h264 640x352 30.288fps)
> (+) Audio --aid=1 (*) (aac 2ch 48000Hz)
> libEGL warning: DRI3: Screen seems not DRI3 capable
> AO: [sdl] 48000Hz stereo 2ch s32
>
> VO: [gpu] 640x352 yuv420p
>
> AV: 00:01:38 / 00:01:38 (100%) A-V: 0.000
>
>
>
>
> Exiting... (End of file)
>
> pthread_mutex_destroy on mutex with waiters!
> Segmentation fault (core dumped)
POSIX says:
"Attempting to destroy a locked mutex, or a mutex that another
thread is attempting to lock, or a mutex that is being used in a
pthread_cond_timedwait() or pthread_cond_wait() call by another
thread, results in undefined behavior."
