diff options
| author | paulhsia <paulhsia@chromium.org> | 2019-11-13 01:17:14 +0800 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2019-11-13 10:51:36 +0100 |
| commit | f5cdc9d4003a2f66ea57b3edd3e04acc2b1a4439 (patch) | |
| tree | a17360281ab0a47bf58eb41881fc1367a2b8395c | |
| parent | 528699317dd6dc722dccc11b68800cf945109390 (diff) | |
| download | linux-f5cdc9d4003a2f66ea57b3edd3e04acc2b1a4439.tar.bz2 | |
ALSA: pcm: Fix stream lock usage in snd_pcm_period_elapsed()
If the nullity check for `substream->runtime` is outside of the lock
region, it is possible to have a null runtime in the critical section
if snd_pcm_detach_substream is called right before the lock.
Signed-off-by: paulhsia <paulhsia@chromium.org>
Link: https://lore.kernel.org/r/20191112171715.128727-2-paulhsia@chromium.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
| -rw-r--r-- | sound/core/pcm_lib.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index d80041ea4e01..2236b5e0c1f2 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -1782,11 +1782,14 @@ void snd_pcm_period_elapsed(struct snd_pcm_substream *substream) struct snd_pcm_runtime *runtime; unsigned long flags; - if (PCM_RUNTIME_CHECK(substream)) + if (snd_BUG_ON(!substream)) return; - runtime = substream->runtime; snd_pcm_stream_lock_irqsave(substream, flags); + if (PCM_RUNTIME_CHECK(substream)) + goto _unlock; + runtime = substream->runtime; + if (!snd_pcm_running(substream) || snd_pcm_update_hw_ptr0(substream, 1) < 0) goto _end; @@ -1797,6 +1800,7 @@ void snd_pcm_period_elapsed(struct snd_pcm_substream *substream) #endif _end: kill_fasync(&runtime->fasync, SIGIO, POLL_IN); + _unlock: snd_pcm_stream_unlock_irqrestore(substream, flags); } EXPORT_SYMBOL(snd_pcm_period_elapsed); |