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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2026-90326

blk-cgroup: fix race between policy activation and blkg destruction

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: fix race between policy activation and blkg destruction When switching an IO scheduler on a block device, blkcg_activate_policy() allocates blkg_policy_data (pd) for all blkgs attached to the queue. However, blkcg_activate_policy() may race with concurrent blkcg deletion, leading to use-after-free and memory leak issues. The use-after-free occurs in the following race: T1 (blkcg_activate_policy): - Successfully allocates pd for blkg1 (loop0->queue, blkcgA) - Fails to allocate pd for blkg2 (loop0->queue, blkcgB) - Enters the enomem rollback path to release blkg1 resources T2 (blkcg deletion): - blkcgA is deleted concurrently - blkg1 is freed via blkg_free_workfn() - blkg1->pd is freed T1 (continued): - Rollback path accesses blkg1->pd->online after pd is freed - Triggers use-after-free In addition, blkg_free_workfn() frees pd before removing the blkg from q->blkg_list. This allows blkcg_activate_policy() to allocate a new pd for a blkg that is being destroyed, leaving the newly allocated pd unreachable when the blkg is finally freed. Fix these races by extending blkcg_mutex coverage to serialize blkcg_activate_policy() rollback and blkg destruction, ensuring pd lifecycle is synchronized with blkg list visibility.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 81c1188905f88b77743d1fdeeedfc8cb7b67787d to < b5dae1cd0d8368b4338430ff93403df67f0b8bccaffected
  • bfe46d2efe46c5c952f982e2ca94fe2ec5e58e2a to < 083b58373463a6e5ee60ecb135269348f68ad7dfaffected
  • f1c006f1c6850c14040f8337753a63119bba39b9 to < 17c18a0df70c2b89ff7fcd74622f1540e98d00fdaffected
  • f1c006f1c6850c14040f8337753a63119bba39b9 to < 91062e3a9ed251726df4e20ff9a1113f1c8ded59affected
  • f1c006f1c6850c14040f8337753a63119bba39b9 to < ac34e655dffa74349d885a43d098115336f53842affected
  • f1c006f1c6850c14040f8337753a63119bba39b9 to < 2cf9f50a38c1839e549a08e22aa35e8d69e2c8fdaffected
  • f1c006f1c6850c14040f8337753a63119bba39b9 to < 5313d4d41739b0cb63000747c97bb1217ac45f3eaffected
  • 6.1.16 to < 6.1.17affected
  • 6.2.3 to < 6.2.4affected

Linux Linux

Default version status: affected

  • 6.3affected
  • 0 to < 6.3unaffected
  • 6.1.17 to ≤ 6.1.*unaffected
  • 6.2.4 to ≤ 6.2.*unaffected
  • 6.6.160 to ≤ 6.6.*unaffected
  • 6.12.114 to ≤ 6.12.*unaffected
  • 6.18.52 to ≤ 6.18.*unaffected
  • 7.2.6 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References