The async signal (SIGIO) support for ALSA PCM API has been never used
by real applications, but yet it can be a cause of various potential
deadlocks, as spotted by syzkaller. Let's drop the feature as the
simplest solution.
Reported-by: syzbot+8285e973a41b5aa68902@xxxxxxxxxxxxxxxxxxxxxxxxx
Reported-by: syzbot+669c9abf11a6a011dd09@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
include/sound/pcm.h | 1 -
sound/core/pcm_lib.c | 8 +-------
sound/core/pcm_native.c | 18 ------------------
3 files changed, 1 insertion(+), 26 deletions(-)
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index 08cf4a5801f3..9bbd3742ef59 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -399,7 +399,6 @@ struct snd_pcm_runtime {
snd_pcm_uframes_t twake; /* do transfer (!poll) wakeup if non-zero */
wait_queue_head_t sleep; /* poll sleep */
wait_queue_head_t tsleep; /* transfer sleep */
- struct fasync_struct *fasync;
bool stop_operating; /* sync_stop will be called */
struct mutex buffer_mutex; /* protect for buffer changes */
atomic_t buffer_accessing; /* >0: in r/w operation, <0: blocked */
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 1fc7c50ffa62..e490a575aa03 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -1807,22 +1807,16 @@ EXPORT_SYMBOL(snd_pcm_lib_ioctl);
*/
void snd_pcm_period_elapsed_under_stream_lock(struct snd_pcm_substream *substream)
{
- struct snd_pcm_runtime *runtime;
-
if (PCM_RUNTIME_CHECK(substream))
return;
- runtime = substream->runtime;
-
if (!snd_pcm_running(substream) ||
snd_pcm_update_hw_ptr0(substream, 1) < 0)
- goto _end;
+ return;
#ifdef CONFIG_SND_PCM_TIMER
if (substream->timer_running)
snd_timer_interrupt(substream->timer, 1);
#endif
- _end:
- kill_fasync(&runtime->fasync, SIGIO, POLL_IN);
}
EXPORT_SYMBOL(snd_pcm_period_elapsed_under_stream_lock);
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index aa0453e51595..c8e340b97277 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -3938,22 +3938,6 @@ static int snd_pcm_mmap(struct file *file, struct vm_area_struct *area)
return 0;
}
-static int snd_pcm_fasync(int fd, struct file * file, int on)
-{
- struct snd_pcm_file * pcm_file;
- struct snd_pcm_substream *substream;
- struct snd_pcm_runtime *runtime;
-
- pcm_file = file->private_data;
- substream = pcm_file->substream;
- if (PCM_RUNTIME_CHECK(substream))
- return -ENXIO;
- runtime = substream->runtime;
- if (runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
- return -EBADFD;
- return fasync_helper(fd, file, on, &runtime->fasync);
-}
-
/*
* ioctl32 compat
*/
@@ -4118,7 +4102,6 @@ const struct file_operations snd_pcm_f_ops[2] = {
.unlocked_ioctl = snd_pcm_ioctl,
.compat_ioctl = snd_pcm_ioctl_compat,
.mmap = snd_pcm_mmap,
- .fasync = snd_pcm_fasync,
.get_unmapped_area = snd_pcm_get_unmapped_area,
},
{
@@ -4132,7 +4115,6 @@ const struct file_operations snd_pcm_f_ops[2] = {
.unlocked_ioctl = snd_pcm_ioctl,
.compat_ioctl = snd_pcm_ioctl_compat,
.mmap = snd_pcm_mmap,
- .fasync = snd_pcm_fasync,
.get_unmapped_area = snd_pcm_get_unmapped_area,
}
};
--
2.35.3
