CVE-2023-53275

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ALSA: hda: fix a possible null-pointer dereference due to data race in snd_hdac_regmap_sync()<br /> <br /> The variable codec-&gt;regmap is often protected by the lock<br /> codec-&gt;regmap_lock when is accessed. However, it is accessed without<br /> holding the lock when is accessed in snd_hdac_regmap_sync():<br /> <br /> if (codec-&gt;regmap)<br /> <br /> In my opinion, this may be a harmful race, because if codec-&gt;regmap is<br /> set to NULL right after the condition is checked, a null-pointer<br /> dereference can occur in the called function regcache_sync():<br /> <br /> map-&gt;lock(map-&gt;lock_arg); --&gt; Line 360 in drivers/base/regmap/regcache.c<br /> <br /> To fix this possible null-pointer dereference caused by data race, the<br /> mutex_lock coverage is extended to protect the if statement as well as the<br /> function call to regcache_sync().<br /> <br /> [ Note: the lack of the regmap_lock itself is harmless for the current<br /> codec driver implementations, as snd_hdac_regmap_sync() is only for<br /> PM runtime resume that is prohibited during the codec probe.<br /> But the change makes the whole code more consistent, so it&amp;#39;s merged<br /> as is -- tiwai ]