Bug 2516462 (CVE-2026-72375)

Summary:	CVE-2026-72375 kernel: afs: Fix reinitialisation of the inode, in particular ->lock_work
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's AFS (Andrew File System) component. This vulnerability arises from improper reinitialization of internal work queue objects, specifically afs_vnode::lock_work. An attacker could potentially exploit this flaw to trigger kernel warnings and lead to system instability, resulting in a denial of service where the system becomes unresponsive.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-08-15 06:13:48 UTC

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.

Comment 1 gkamathe 2026-08-18 12:09:32 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081516-CVE-2026-72375-a181@gregkh/T