CVE-2026-89566

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

jbd2: check need_resched() when skipping busy checkpoint buffers

journal_shrink_one_cp_list() skips busy checkpoint buffers when called

with JBD2_SHRINK_BUSY_SKIP. The continue statement on this path also

skips the need_resched() check at the end of the loop body.

Consequently, when a checkpoint list contains mostly busy buffers, the

shrinker can walk the entire list while holding journal->j_list_lock,

even when a reschedule has been requested. Large checkpoint lists under

memory pressure can therefore cause long lock hold times and leave other

CPUs spinning on j_list_lock, resulting in soft lockups or RCU stalls.

Route the busy-buffer path through the need_resched() check so that the

shrinker can release j_list_lock and reschedule promptly, restoring

parity with the clean-buffer path, which already checks need_resched().

This does not change which checkpoint buffers are eligible for removal.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References