"value":"In the Linux kernel, the following vulnerability has been resolved:\n\ngfs2: Fix potential glock use-after-free on unmount\n\nWhen a DLM lockspace is released and there ares still locks in that\nlockspace, DLM will unlock those locks automatically. Commit\nfb6791d100d1b started exploiting this behavior to speed up filesystem\nunmount: gfs2 would simply free glocks it didn't want to unlock and then\nrelease the lockspace. This didn't take the bast callbacks for\nasynchronous lock contention notifications into account, which remain\nactive until until a lock is unlocked or its lockspace is released.\n\nTo prevent those callbacks from accessing deallocated objects, put the\nglocks that should not be unlocked on the sd_dead_glocks list, release\nthe lockspace, and only then free those glocks.\n\nAs an additional measure, ignore unexpected ast and bast callbacks if\nthe receiving glock is dead."