Copyright © 2012 Red Hat, Inc. All rights reserved. Low 2026-09-11T00:00:00 kernel: jbd2: check need_resched() when skipping busy checkpoint buffers 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-606

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.

A flaw was found in the Linux kernel's jbd2 component. When the kernel's journaling block device (jbd2) processes busy checkpoint buffers, it can skip a crucial rescheduling check. This oversight can lead to prolonged holding of a critical lock, causing other central processing units (CPUs) to wait indefinitely. Consequently, this can result in system unresponsiveness, known as soft lockups or RCU stalls, effectively causing a Denial of Service (DoS).

Red Hat Enterprise Linux 10 Fix deferred kernel Red Hat Enterprise Linux 6 Out of support scope kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Fix deferred kernel Red Hat Enterprise Linux 9 Fix deferred kernel-rt Red Hat OpenShift Container Platform 4 Not affected openshift/ose-rhel-coreos-8 Red Hat OpenShift Container Platform 4 Fix deferred openshift/ose-rhel-coreos-9 https://www.cve.org/CVERecord?id=CVE-2026-89566 https://nvd.nist.gov/vuln/detail/CVE-2026-89566 https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89566.mbox