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authorAndrew Gabbasov <andrew_gabbasov@mentor.com>2019-11-27 05:06:22 -0600
committerTakashi Iwai <tiwai@suse.de>2019-11-27 12:16:00 +0100
commit5061bb7065d05efbac35a660eb30ed4c3100690b (patch)
tree3df2de81053fc1a7409afc5b92d0095688289b83
parent8218df93b7c4b1c6d02c4f726029e10efa4b7ca2 (diff)
downloadlinux-5061bb7065d05efbac35a660eb30ed4c3100690b.tar.bz2
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>
-rw-r--r--sound/drivers/aloop.c8
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;