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| author | Andrew Gabbasov <andrew_gabbasov@mentor.com> | 2019-11-27 05:06:22 -0600 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2019-11-27 12:16:00 +0100 |
| commit | 5061bb7065d05efbac35a660eb30ed4c3100690b (patch) | |
| tree | 3df2de81053fc1a7409afc5b92d0095688289b83 /sound | |
| parent | 8218df93b7c4b1c6d02c4f726029e10efa4b7ca2 (diff) | |
| download | lwn-5061bb7065d05efbac35a660eb30ed4c3100690b.tar.gz lwn-5061bb7065d05efbac35a660eb30ed4c3100690b.zip | |
ALSA: aloop: Avoid pointer dereference before null-check
Static analysis tools (cppcheck and PVS Studio) report an error
in loopback_snd_timer_period_elapsed() regarding dpcm_play pointer
dereference earlier than its null-check. And although this is a result
of a formal check, and the pointer correctness is also protected
by having a corresponding bit set in the "running" mask, re-ordering
of the lines can imake the code even formally correct and eliminate
those static analysis error reports.
Fixes: 26c53379f98d ("ALSA: aloop: Support selection of snd_timer instead of jiffies")
Reported-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
Link: https://lore.kernel.org/r/20191127110622.26105-1-andrew_gabbasov@mentor.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
| -rw-r--r-- | sound/drivers/aloop.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c index 0ebfbe70db00..6bb46423f5ae 100644 --- a/sound/drivers/aloop.c +++ b/sound/drivers/aloop.c @@ -727,10 +727,6 @@ static void loopback_snd_timer_period_elapsed(struct loopback_cable *cable, dpcm_play = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]; dpcm_capt = cable->streams[SNDRV_PCM_STREAM_CAPTURE]; - substream_play = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? - dpcm_play->substream : NULL; - substream_capt = (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) ? - dpcm_capt->substream : NULL; if (event == SNDRV_TIMER_EVENT_MSTOP) { if (!dpcm_play || @@ -741,6 +737,10 @@ static void loopback_snd_timer_period_elapsed(struct loopback_cable *cable, } } + substream_play = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? + dpcm_play->substream : NULL; + substream_capt = (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) ? + dpcm_capt->substream : NULL; valid_runtime = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? dpcm_play->substream->runtime : dpcm_capt->substream->runtime; |