In the Linux kernel, the following vulnerability has been resolved: futex: Fix UaF between futexkeytonodeopt() and vmareplacepolicy() During futexkeytonodeopt() execution, vma->vmpolicy is read under speculative mmap lock and RCU. Concurrently, mbind() may call vmareplacepolicy() which frees the old mempolicy immediately via kmemcache_free(). This creates a race where __futexkeyto_node() dereferences a freed mempolicy pointer, causing a use-after-free read of mpol->mode. [ 151.412631] BUG: KASAN: slab-use-after-free in __futexkeyto_node (kernel/futex/core.c:349) [ 151.414046] Read of size 2 at addr ffff888001c49634 by task e/87 [ 151.415969] Call Trace: [ 151.416732] __asan_load2 (mm/kasan/generic.c:271) [ 151.416777] __futexkeytonode (kernel/futex/core.c:349) [ 151.416822] getfutex_key (kernel/futex/core.c:374 kernel/futex/core.c:386 kernel/futex/core.c:593) Fix by adding rcu to _mpolput().