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| author | Takashi Iwai <tiwai@suse.de> | 2016-04-14 18:02:37 +0200 |
|---|---|---|
| committer | Simon Shields <keepcalm444@gmail.com> | 2017-01-08 23:55:35 +1100 |
| commit | d366ce9f4a0b8bd1614559a0582279832f041176 (patch) | |
| tree | 9c090f7eda83d69118f254fe562c8d3766fce63a | |
| parent | 23e09dca1062825ecbac06d9a56c1b745d7bd774 (diff) | |
| download | kernel_samsung_smdk4412-d366ce9f4a0b8bd1614559a0582279832f041176.zip kernel_samsung_smdk4412-d366ce9f4a0b8bd1614559a0582279832f041176.tar.gz kernel_samsung_smdk4412-d366ce9f4a0b8bd1614559a0582279832f041176.tar.bz2 | |
ALSA: pcm : Call kill_fasync() in stream lock
Currently kill_fasync() is called outside the stream lock in
snd_pcm_period_elapsed(). This is potentially racy, since the stream
may get released even during the irq handler is running. Although
snd_pcm_release_substream() calls snd_pcm_drop(), this doesn't
guarantee that the irq handler finishes, thus the kill_fasync() call
outside the stream spin lock may be invoked after the substream is
detached, as recently reported by KASAN.
As a quick workaround, move kill_fasync() call inside the stream
lock. The fasync is rarely used interface, so this shouldn't have a
big impact from the performance POV.
Ideally, we should implement some sync mechanism for the proper finish
of stream and irq handler. But this oneliner should suffice for most
cases, so far.
Change-Id: I5dbc5260abe527261b4b8c4699400b317af8451e
Reported-by: Baozeng Ding <sploving1@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
| -rw-r--r-- | sound/core/pcm_lib.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 397d9ad..6acd47a 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -1734,10 +1734,10 @@ void snd_pcm_period_elapsed(struct snd_pcm_substream *substream) if (substream->timer_running) snd_timer_interrupt(substream->timer, 1); _end: - snd_pcm_stream_unlock_irqrestore(substream, flags); if (runtime->transfer_ack_end) runtime->transfer_ack_end(substream); kill_fasync(&runtime->fasync, SIGIO, POLL_IN); + snd_pcm_stream_unlock_irqrestore(substream, flags); } EXPORT_SYMBOL(snd_pcm_period_elapsed); |