diff options
| author | Tuo Li <islituo@gmail.com> | 2023-07-03 11:10:16 +0800 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2023-07-03 10:08:12 +0200 |
| commit | 1f4a08fed450db87fbb5ff5105354158bdbe1a22 (patch) | |
| tree | f079a1a65d8a0629fdf4a54c8192a047a082bbd1 /sound/hda | |
| parent | 73f1c75d5e6bd8ce2a887ef493a66ad1b16ed704 (diff) | |
ALSA: hda: fix a possible null-pointer dereference due to data race in snd_hdac_regmap_sync()
The variable codec->regmap is often protected by the lock
codec->regmap_lock when is accessed. However, it is accessed without
holding the lock when is accessed in snd_hdac_regmap_sync():
if (codec->regmap)
In my opinion, this may be a harmful race, because if codec->regmap is
set to NULL right after the condition is checked, a null-pointer
dereference can occur in the called function regcache_sync():
map->lock(map->lock_arg); --> Line 360 in drivers/base/regmap/regcache.c
To fix this possible null-pointer dereference caused by data race, the
mutex_lock coverage is extended to protect the if statement as well as the
function call to regcache_sync().
[ Note: the lack of the regmap_lock itself is harmless for the current
codec driver implementations, as snd_hdac_regmap_sync() is only for
PM runtime resume that is prohibited during the codec probe.
But the change makes the whole code more consistent, so it's merged
as is -- tiwai ]
Reported-by: BassCheck <bass@buaa.edu.cn>
Signed-off-by: Tuo Li <islituo@gmail.com>
Link: https://lore.kernel.org/r/20230703031016.1184711-1-islituo@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/hda')
| -rw-r--r-- | sound/hda/hdac_regmap.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/sound/hda/hdac_regmap.c b/sound/hda/hdac_regmap.c index f258cb3a6895..9b1bcabd8414 100644 --- a/sound/hda/hdac_regmap.c +++ b/sound/hda/hdac_regmap.c @@ -596,10 +596,9 @@ EXPORT_SYMBOL_GPL(snd_hdac_regmap_update_raw_once); */ void snd_hdac_regmap_sync(struct hdac_device *codec) { - if (codec->regmap) { - mutex_lock(&codec->regmap_lock); + mutex_lock(&codec->regmap_lock); + if (codec->regmap) regcache_sync(codec->regmap); - mutex_unlock(&codec->regmap_lock); - } + mutex_unlock(&codec->regmap_lock); } EXPORT_SYMBOL_GPL(snd_hdac_regmap_sync); |