CVE-2024-38570

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