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Benjamin Marzinski
c499d0799a
JIRA: https://issues.redhat.com/browse/RHEL-231823 CVE: CVE-2026-53062 Upstream Status: kernel/git/torvalds/linux.git commit d3f0a606b9f278ece8a0df626ded9c4044071235 Author: Guangshuo Li <lgs201920130244@gmail.com> Date: Fri May 29 23:57:45 2026 +0800 dm cache policy smq: check allocation under invalidate lock commit 2d1f7b65f5de ("dm cache policy smq: fix missing locks in invalidating cache blocks") added mq->lock around the destructive part of smq_invalidate_mapping(), but left the e->allocated check outside the critical section. That leaves a check-then-act race. Two concurrent invalidators can both observe e->allocated as true before either of them takes mq->lock. The first invalidator that acquires the lock removes the entry from the queues and hash table and then calls free_entry(), which clears e->allocated and puts the entry back on the free list. The second invalidator can then acquire mq->lock and continue with the stale result of the unlocked check. This can corrupt the SMQ queues or hash table by deleting an entry that is no longer on those structures. It can also hit the allocation check in free_entry() when the same entry is freed again. Move the allocation check under mq->lock so the predicate and the destructive operations are serialized by the same lock. Fixes: 2d1f7b65f5de ("dm cache policy smq: fix missing locks in invalidating cache blocks") Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>