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pthread_frame: use a thread-safe way for signalling threads to die 

Current code uses a plain int in a racy way, which is UB.
This commit is contained in:
Anton Khirnov 2016-07-17 23:30:52 +02:00
parent 8385ba53f1
commit db2733256d
1 changed files with 11 additions and 9 deletions
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20
libavcodec/pthread_frame.c
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@ -90,6 +90,8 @@ typedef struct PerThreadContext {
AVFrame *requested_frame; ///< AVFrame the codec passed to get_buffer()
int requested_flags; ///< flags passed to get_buffer() for requested_frame
int die; ///< Set when the thread should exit.
} PerThreadContext;
/**
@ -108,8 +110,6 @@ typedef struct FrameThreadContext {
* Set for the first N packets, where N is the number of threads.
* While it is set, ff_thread_en/decode_frame won't return any results.
*/
int die; ///< Set when threads should exit.
} FrameThreadContext;
/**
@ -122,20 +122,22 @@ typedef struct FrameThreadContext {
static attribute_align_arg void *frame_worker_thread(void *arg)
{
PerThreadContext *p = arg;
FrameThreadContext *fctx = p->parent;
AVCodecContext *avctx = p->avctx;
const AVCodec *codec = avctx->codec;
while (1) {
if (p->state == STATE_INPUT_READY && !fctx->die) {
if (p->state == STATE_INPUT_READY) {
pthread_mutex_lock(&p->mutex);
while (p->state == STATE_INPUT_READY && !fctx->die)
while (p->state == STATE_INPUT_READY) {
if (p->die) {
pthread_mutex_unlock(&p->mutex);
goto die;
}
pthread_cond_wait(&p->input_cond, &p->mutex);
}
pthread_mutex_unlock(&p->mutex);
}
if (fctx->die) break;
if (!codec->update_thread_context && avctx->thread_safe_callbacks)
ff_thread_finish_setup(avctx);
@ -161,6 +163,7 @@ static attribute_align_arg void *frame_worker_thread(void *arg)
pthread_mutex_unlock(&p->mutex);
}
die:
return NULL;
}
@ -504,12 +507,11 @@ void ff_frame_thread_free(AVCodecContext *avctx, int thread_count)
if (fctx->prev_thread && fctx->prev_thread != fctx->threads)
update_context_from_thread(fctx->threads->avctx, fctx->prev_thread->avctx, 0);
fctx->die = 1;
for (i = 0; i < thread_count; i++) {
PerThreadContext *p = &fctx->threads[i];
pthread_mutex_lock(&p->mutex);
p->die = 1;
pthread_cond_signal(&p->input_cond);
pthread_mutex_unlock(&p->mutex);