CVE-2026-72375: afs: Fix reinitialisation of the inode, in particular ->lock_work

CVE-2026-72375: afs: Fix reinitialisation of the inode, in particular ->lock_work

[Greg Kroah-Hartman]

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

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

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

afs: Fix reinitialisation of the inode, in particular ->lock_work

It seems that initalising afs_vnode::lock_work a single time in the slab's
init function isn't sufficient for work_structs.  This results in the
DEBUG_OBJECTS debugging stuff producing a warning occasionally when running
the generic/131 xfstest:

 ODEBUG: activate not available (active state 0) object: 0000000016d8760f object type: work_struct hint: afs_lock_work+0x0/0x220
 WARNING: lib/debugobjects.c:629 at debug_print_object+0x4b/0x90, CPU#3: locktest/7695
 ...
 CPU: 3 UID: 0 PID: 7695 Comm: locktest Tainted: G S                  7.1.0-build3+ #2771 PREEMPT
 ...
 RIP: 0010:debug_print_object+0x65/0x90
 ...
 Call Trace:
  <TASK>
  ? __pfx_afs_lock_work+0x10/0x10
  debug_object_activate+0x122/0x170
  insert_work+0x25/0x60
  __queue_work+0x2e0/0x340
  queue_delayed_work_on+0x48/0x70
  afs_fl_release_private+0x57/0x70
  locks_release_private+0x5c/0xa0
  locks_free_lock+0xe/0x20
  posix_lock_inode+0x55f/0x5b0
  locks_lock_inode_wait+0x81/0x140
  ? file_write_and_wait_range+0x50/0x70
  afs_lock+0xcd/0x110
  fcntl_setlk+0x10d/0x260
  do_fcntl+0x24e/0x5b0
  __do_sys_fcntl+0x6a/0x90
  do_syscall_64+0x11e/0x310
  entry_SYSCALL_64_after_hwframe+0x71/0x79

Fix this by reinitialising ->lock_work after allocating an inode.

Also, flush ->lock_work when the inode is being evicted to make sure it's
not still running.

The Linux kernel CVE team has assigned CVE-2026-72375 to this issue.


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

	Issue introduced in 2.6.23 with commit e8d6c554126b830217c5e9f549e0e21f865a0a8a and fixed in 6.18.40 with commit 63d3f283858fae097fb09ddd4ce46bb0bc1f9d01
	Issue introduced in 2.6.23 with commit e8d6c554126b830217c5e9f549e0e21f865a0a8a and fixed in 7.1.5 with commit ebfd13c0367adb43d7c0a72f5cd7e004e60c6b28
	Issue introduced in 2.6.23 with commit e8d6c554126b830217c5e9f549e0e21f865a0a8a and fixed in 7.2-rc2 with commit 5597fbd1e7c161914f20315a726e54025b0fdadb

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-2026-72375
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/afs/inode.c
	fs/afs/super.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/63d3f283858fae097fb09ddd4ce46bb0bc1f9d01
	https://git.kernel.org/stable/c/ebfd13c0367adb43d7c0a72f5cd7e004e60c6b28
	https://git.kernel.org/stable/c/5597fbd1e7c161914f20315a726e54025b0fdadb