Bug 2516654 (CVE-2026-72161)

Summary: CVE-2026-72161 kernel: ocfs2: add journal NULL check in ocfs2_checkpoint_inode()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the ocfs2 component of the Linux kernel. A local user could trigger a NULL pointer dereference during the unmount process of an ocfs2 filesystem. This occurs because the system attempts to access a freed journal pointer, leading to a system crash and a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-08-15 06:24:10 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ocfs2: add journal NULL check in ocfs2_checkpoint_inode()

During unmount, ocfs2_journal_shutdown() frees the journal and sets
osb->journal to NULL. Later, when VFS evicts remaining cached inodes,
ocfs2_evict_inode() -> ocfs2_clear_inode() -> ocfs2_checkpoint_inode()
-> ocfs2_ci_fully_checkpointed() dereferences osb->journal, causing a
NULL pointer dereference.

Fix this by adding a NULL check for osb->journal in
ocfs2_checkpoint_inode(). If the journal is NULL, it has already been
fully flushed and destroyed during shutdown, so there is nothing to
checkpoint.
Comment 1 Keith Grant 2026-08-18 13:29:52 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081536-CVE-2026-72161-c625@gregkh/T