GHSA-QVXH-98Q9-X4J8
Vulnerability from github – Published: 2026-06-24 18:32 – Updated: 2026-06-24 18:32In 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 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
Reproduce steps:
- 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"
- Promote the first data block into cache
fio --filename=/dev/mapper/cache --name=populate --rw=write --bs=4k \ --direct=1 --size=64k
- 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
- 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.
{
"affected": [],
"aliases": [
"CVE-2026-53064"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-24T17:17:19Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm cache: fix null-deref with concurrent writes in passthrough mode\n\nIn passthrough mode, when dm-cache starts to invalidate a cache\nentry and bio prison cell lock fails due to concurrent write to\nthe same cached block, mg-\u003ecell remains NULL. The error path in\ninvalidate_complete() attempts to unlock and free the cell\nunconditionally, causing a NULL pointer dereference:\n\nKASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]\nCPU: 0 UID: 0 PID: 134 Comm: fio Not tainted 6.19.0-rc7 #3 PREEMPT\nRIP: 0010:dm_cell_unlock_v2+0x3f/0x210\n\u003csnip\u003e\nCall Trace:\n invalidate_complete+0xef/0x430\n map_bio+0x130f/0x1a10\n cache_map+0x320/0x6b0\n __map_bio+0x458/0x510\n dm_submit_bio+0x40e/0x16d0\n __submit_bio+0x419/0x870\n\u003csnip\u003e\n\nReproduce steps:\n\n1. Create a cache device\n\ndmsetup create cmeta --table \"0 8192 linear /dev/sdc 0\"\ndmsetup create cdata --table \"0 131072 linear /dev/sdc 8192\"\ndmsetup create corig --table \"0 262144 linear /dev/sdc 262144\"\ndd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct\ndmsetup create cache --table \"0 262144 cache /dev/mapper/cmeta \\\n/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0\"\n\n2. Promote the first data block into cache\n\nfio --filename=/dev/mapper/cache --name=populate --rw=write --bs=4k \\\n--direct=1 --size=64k\n\n3. Reload the cache into passthrough mode\n\ndmsetup suspend cache\ndmsetup reload cache --table \"0 262144 cache /dev/mapper/cmeta \\\n/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 passthrough smq 0\"\ndmsetup resume cache\n\n4. Write to the first cached block concurrently\n\nfio --filename=/dev/mapper/cache --name test --rw=randwrite --bs=4k \\\n--randrepeat=0 --direct=1 --numjobs=2 --size 64k\n\nFix by checking if mg-\u003ecell is valid before attempting to unlock it.",
"id": "GHSA-qvxh-98q9-x4j8",
"modified": "2026-06-24T18:32:45Z",
"published": "2026-06-24T18:32:45Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53064"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/01264a6a3a3ad7ac1d73443299cd5a9568002454"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0aa745fea1f8dc81bcdd0a45e215b6706727b482"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/25dcc1989c194ba2b5fb6d03cbb9b83814ac0d15"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7d1f98d668ee34c1d15bdc0420fdd062f24a27c0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a2635d541a93fd111e743cf14b6275dc81be2abc"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c7fb6bc864c4910b344dafa36dd5028e9b980768"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/df3b8ef06cc62de4fca5d2108e285085b3cffd44"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ee38fb00e1a80f46a4990e38f25ecb04ae7b7417"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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