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authorpaulhsia <paulhsia@chromium.org>2019-11-13 01:17:14 +0800
committerTakashi Iwai <tiwai@suse.de>2019-11-13 10:51:36 +0100
commitf5cdc9d4003a2f66ea57b3edd3e04acc2b1a4439 (patch)
treea17360281ab0a47bf58eb41881fc1367a2b8395c /sound/core
parent528699317dd6dc722dccc11b68800cf945109390 (diff)
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>
Diffstat (limited to 'sound/core')
-rw-r--r--sound/core/pcm_lib.c8
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);