CVE-2026-72161: ocfs2: add journal NULL check in ocfs2_checkpoint_inode()

CVE-2026-72161: ocfs2: add journal NULL check in ocfs2_checkpoint_inode()

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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.

The Linux kernel CVE team has assigned CVE-2026-72161 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.16 with commit da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 and fixed in 6.1.178 with commit 24daf13422e8328fd588c34a017bdef1949910e8
	Issue introduced in 5.16 with commit da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 and fixed in 6.6.145 with commit 7da7e4ac21895fe34cceffcfc99497cc2750da99
	Issue introduced in 5.16 with commit da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 and fixed in 6.12.97 with commit eb6a13834c23e291f1170cb1b489ec255edfa5a3
	Issue introduced in 5.16 with commit da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 and fixed in 6.18.40 with commit 499714de42ab4d2e778cbb10186684142a1222eb
	Issue introduced in 5.16 with commit da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 and fixed in 7.1.5 with commit 63921f790234b221e4b15c56c72888b13250f81d
	Issue introduced in 5.16 with commit da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 and fixed in 7.2-rc1 with commit a291c77c034b7a81849ce9b71cc9ecda9e587d89

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-72161
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	fs/ocfs2/journal.h


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/24daf13422e8328fd588c34a017bdef1949910e8
	https://git.kernel.org/stable/c/7da7e4ac21895fe34cceffcfc99497cc2750da99
	https://git.kernel.org/stable/c/eb6a13834c23e291f1170cb1b489ec255edfa5a3
	https://git.kernel.org/stable/c/499714de42ab4d2e778cbb10186684142a1222eb
	https://git.kernel.org/stable/c/63921f790234b221e4b15c56c72888b13250f81d
	https://git.kernel.org/stable/c/a291c77c034b7a81849ce9b71cc9ecda9e587d89