CVE-2024-38570

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> gfs2: Fix potential glock use-after-free on unmount<br /> <br /> When a DLM lockspace is released and there ares still locks in that<br /> lockspace, DLM will unlock those locks automatically. Commit<br /> fb6791d100d1b started exploiting this behavior to speed up filesystem<br /> unmount: gfs2 would simply free glocks it didn&amp;#39;t want to unlock and then<br /> release the lockspace. This didn&amp;#39;t take the bast callbacks for<br /> asynchronous lock contention notifications into account, which remain<br /> active until until a lock is unlocked or its lockspace is released.<br /> <br /> To prevent those callbacks from accessing deallocated objects, put the<br /> glocks that should not be unlocked on the sd_dead_glocks list, release<br /> the lockspace, and only then free those glocks.<br /> <br /> As an additional measure, ignore unexpected ast and bast callbacks if<br /> the receiving glock is dead.