CVE-2026-72189: ntfs: fail attrlist updates when the superblock is inactive

CVE-2026-72189: ntfs: fail attrlist updates when the superblock is inactive

[Greg Kroah-Hartman]

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

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

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

ntfs: fail attrlist updates when the superblock is inactive

generic_shutdown_super() clears SB_ACTIVE before evicting cached inodes.
If eviction selects the fake inode for a base inode's unnamed
$ATTRIBUTE_LIST attribute, ntfs_evict_big_inode() drops the fake inode's
reference on the base inode while the fake inode is still hashed and marked
I_FREEING.

That iput can synchronously write back the base inode. The writeback path
may update mapping pairs and call ntfs_attrlist_update(), which
unconditionally calls ntfs_attr_iget() for the same $ATTRIBUTE_LIST fake
inode. VFS then finds the I_FREEING inode and waits for eviction to finish,
but the current task is still inside that eviction path, causing a
self-deadlock in find_inode().

Fix this by mirroring the teardown guard used by __ntfs_write_inode():
once SB_ACTIVE has been cleared, do not try to iget the attribute-list
fake inode. Return -EIO so teardown aborts the update instead of waiting on
the inode it is evicting.

The Linux kernel CVE team has assigned CVE-2026-72189 to this issue.


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

	Issue introduced in 7.1 with commit 495e90fa334828d4119061e2726af51d0a0fb4ed and fixed in 7.1.5 with commit d5379035355c0dcb1e92a2544d40f48441e1d637
	Issue introduced in 7.1 with commit 495e90fa334828d4119061e2726af51d0a0fb4ed and fixed in 7.2-rc3 with commit 0ebe8f625ab0520217a425d7cd366e4670484941

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-2026-72189
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/ntfs/attrlist.c


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/d5379035355c0dcb1e92a2544d40f48441e1d637
	https://git.kernel.org/stable/c/0ebe8f625ab0520217a425d7cd366e4670484941