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| author | Takashi Iwai <tiwai@suse.de> | 2018-01-01 11:50:50 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2018-01-02 16:52:45 +0300 |
| commit | fe08f34d066f4404934a509b6806db1a4f700c86 (patch) | |
| tree | b19b22801cbd3d2f8127c671a30f950b6c8b9f3b /sound/core | |
| parent | 44be77c590f381bc629815ac789b8b15ecc4ddcf (diff) | |
| download | linux-fe08f34d066f4404934a509b6806db1a4f700c86.tar.xz | |
ALSA: pcm: Remove incorrect snd_BUG_ON() usages
syzkaller triggered kernel warnings through PCM OSS emulation at
closing a stream:
WARNING: CPU: 0 PID: 3502 at sound/core/pcm_lib.c:1635
snd_pcm_hw_param_first+0x289/0x690 sound/core/pcm_lib.c:1635
Call Trace:
....
snd_pcm_hw_param_near.constprop.27+0x78d/0x9a0 sound/core/oss/pcm_oss.c:457
snd_pcm_oss_change_params+0x17d3/0x3720 sound/core/oss/pcm_oss.c:969
snd_pcm_oss_make_ready+0xaa/0x130 sound/core/oss/pcm_oss.c:1128
snd_pcm_oss_sync+0x257/0x830 sound/core/oss/pcm_oss.c:1638
snd_pcm_oss_release+0x20b/0x280 sound/core/oss/pcm_oss.c:2431
__fput+0x327/0x7e0 fs/file_table.c:210
....
This happens while it tries to open and set up the aloop device
concurrently. The warning above (invoked from snd_BUG_ON() macro) is
to detect the unexpected logical error where snd_pcm_hw_refine() call
shouldn't fail. The theory is true for the case where the hw_params
config rules are static. But for an aloop device, the hw_params rule
condition does vary dynamically depending on the connected target;
when another device is opened and changes the parameters, the device
connected in another side is also affected, and it caused the error
from snd_pcm_hw_refine().
That is, the simplest "solution" for this is to remove the incorrect
assumption of static rules, and treat such an error as a normal error
path. As there are a couple of other places using snd_BUG_ON()
incorrectly, this patch removes these spurious snd_BUG_ON() calls.
Reported-by: syzbot+6f11c7e2a1b91d466432@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core')
| -rw-r--r-- | sound/core/oss/pcm_oss.c | 1 | ||||
| -rw-r--r-- | sound/core/pcm_lib.c | 4 |
2 files changed, 2 insertions, 3 deletions
diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c index e49f448ee04f..ceaa51f76591 100644 --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -455,7 +455,6 @@ static int snd_pcm_hw_param_near(struct snd_pcm_substream *pcm, v = snd_pcm_hw_param_last(pcm, params, var, dir); else v = snd_pcm_hw_param_first(pcm, params, var, dir); - snd_BUG_ON(v < 0); return v; } diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 10e7ef7a8804..db7894bb028c 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -1632,7 +1632,7 @@ int snd_pcm_hw_param_first(struct snd_pcm_substream *pcm, return changed; if (params->rmask) { int err = snd_pcm_hw_refine(pcm, params); - if (snd_BUG_ON(err < 0)) + if (err < 0) return err; } return snd_pcm_hw_param_value(params, var, dir); @@ -1678,7 +1678,7 @@ int snd_pcm_hw_param_last(struct snd_pcm_substream *pcm, return changed; if (params->rmask) { int err = snd_pcm_hw_refine(pcm, params); - if (snd_BUG_ON(err < 0)) + if (err < 0) return err; } return snd_pcm_hw_param_value(params, var, dir); |