In the Linux kernel, the following vulnerability has been resolved:
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.
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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | unaffected |
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Advisories
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Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Thu, 25 Jun 2026 09:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: 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. | |
| Title | dm cache policy smq: check allocation under invalidate lock | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-06-25T08:39:52.543Z
Reserved: 2026-06-09T07:44:35.395Z
Link: CVE-2026-53265
Vulnrichment
No data.
NVD
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Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.