In the Linux kernel, the following vulnerability has been resolved: md: fix a crash in mempool_free There's a crash in mempool_free when running the lvm test shell/lvchange-rebuild-raid.sh. The reason for the crash is this: * super_written calls atomic_dec_and_test(&mddev->pending_writes) and wake_up(&mddev->sb_wait). Then it calls rdev_dec_pending(rdev, mddev) and bio_put(bio). * so, the process that waited on sb_wait and that is woken up is racing with bio_put(bio). * if the process wins the race, it calls bioset_exit before bio_put(bio) is executed. * bio_put(bio) attempts to free a bio into a destroyed bio set - causing a crash in mempool_free. We fix this bug by moving bio_put before atomic_dec_and_test. We also move rdev_dec_pending before atomic_dec_and_test as sugges