dm cache: fix null-deref with concurrent writes in passthrough mode

Summary

CVECVE-2026-53064
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-24 17:17:19 UTC
Updated2026-06-24 17:17:19 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: dm cache: fix null-deref with concurrent writes in passthrough mode In passthrough mode, when dm-cache starts to invalidate a cache entry and bio prison cell lock fails due to concurrent write to the same cached block, mg->cell remains NULL. The error path in invalidate_complete() attempts to unlock and free the cell unconditionally, causing a NULL pointer dereference: KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 UID: 0 PID: 134 Comm: fio Not tainted 6.19.0-rc7 #3 PREEMPT RIP: 0010:dm_cell_unlock_v2+0x3f/0x210 <snip> Call Trace: invalidate_complete+0xef/0x430 map_bio+0x130f/0x1a10 cache_map+0x320/0x6b0 __map_bio+0x458/0x510 dm_submit_bio+0x40e/0x16d0 __submit_bio+0x419/0x870 <snip> Reproduce steps: 1. Create a cache device dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 131072 linear /dev/sdc 8192" dmsetup create corig --table "0 262144 linear /dev/sdc 262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table "0 262144 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" 2. Promote the first data block into cache fio --filename=/dev/mapper/cache --name=populate --rw=write --bs=4k \ --direct=1 --size=64k 3. Reload the cache into passthrough mode dmsetup suspend cache dmsetup reload cache --table "0 262144 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 passthrough smq 0" dmsetup resume cache 4. Write to the first cached block concurrently fio --filename=/dev/mapper/cache --name test --rw=randwrite --bs=4k \ --randrepeat=0 --direct=1 --numjobs=2 --size 64k Fix by checking if mg->cell is valid before attempting to unlock it.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected b29d4986d0da1a27cd35917cdb433672f5c95d7f 01264a6a3a3ad7ac1d73443299cd5a9568002454 git Not specified
CNA Linux Linux affected b29d4986d0da1a27cd35917cdb433672f5c95d7f ee38fb00e1a80f46a4990e38f25ecb04ae7b7417 git Not specified
CNA Linux Linux affected b29d4986d0da1a27cd35917cdb433672f5c95d7f c7fb6bc864c4910b344dafa36dd5028e9b980768 git Not specified
CNA Linux Linux affected b29d4986d0da1a27cd35917cdb433672f5c95d7f 0aa745fea1f8dc81bcdd0a45e215b6706727b482 git Not specified
CNA Linux Linux affected b29d4986d0da1a27cd35917cdb433672f5c95d7f a2635d541a93fd111e743cf14b6275dc81be2abc git Not specified
CNA Linux Linux affected b29d4986d0da1a27cd35917cdb433672f5c95d7f 25dcc1989c194ba2b5fb6d03cbb9b83814ac0d15 git Not specified
CNA Linux Linux affected b29d4986d0da1a27cd35917cdb433672f5c95d7f df3b8ef06cc62de4fca5d2108e285085b3cffd44 git Not specified
CNA Linux Linux affected b29d4986d0da1a27cd35917cdb433672f5c95d7f 7d1f98d668ee34c1d15bdc0420fdd062f24a27c0 git Not specified
CNA Linux Linux affected 4.12 Not specified
CNA Linux Linux unaffected 4.12 semver Not specified
CNA Linux Linux unaffected 5.10.258 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.209 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.175 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.141 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.91 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.33 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.10 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/01264a6a3a3ad7ac1d73443299cd5a9568002454 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/25dcc1989c194ba2b5fb6d03cbb9b83814ac0d15 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ee38fb00e1a80f46a4990e38f25ecb04ae7b7417 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0aa745fea1f8dc81bcdd0a45e215b6706727b482 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a2635d541a93fd111e743cf14b6275dc81be2abc 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7d1f98d668ee34c1d15bdc0420fdd062f24a27c0 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/df3b8ef06cc62de4fca5d2108e285085b3cffd44 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c7fb6bc864c4910b344dafa36dd5028e9b980768 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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