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ALSA: pcm: Fix stream lock usage in snd_pcm_period_elapsed()
[ Upstream commit f5cdc9d400
]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
f506ed5538
commit
1da0c5d2dc
1 changed files with 6 additions and 2 deletions
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@ -1803,11 +1803,14 @@ void snd_pcm_period_elapsed(struct snd_pcm_substream *substream)
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struct snd_pcm_runtime *runtime;
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unsigned long flags;
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if (PCM_RUNTIME_CHECK(substream))
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if (snd_BUG_ON(!substream))
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return;
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runtime = substream->runtime;
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snd_pcm_stream_lock_irqsave(substream, flags);
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if (PCM_RUNTIME_CHECK(substream))
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goto _unlock;
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runtime = substream->runtime;
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if (!snd_pcm_running(substream) ||
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snd_pcm_update_hw_ptr0(substream, 1) < 0)
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goto _end;
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@ -1818,6 +1821,7 @@ void snd_pcm_period_elapsed(struct snd_pcm_substream *substream)
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#endif
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_end:
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kill_fasync(&runtime->fasync, SIGIO, POLL_IN);
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_unlock:
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snd_pcm_stream_unlock_irqrestore(substream, flags);
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}
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EXPORT_SYMBOL(snd_pcm_period_elapsed);
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