linux-cve-announce - CVE-2025-71105: f2fs: use global inline_xattr

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Message-ID: <2026011410-CVE-2025-71105-2fbe@gregkh>
Date: Wed, 14 Jan 2026 16:06:10 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-71105: f2fs: use global inline_xattr_slab instead of per-sb slab cache

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

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

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

f2fs: use global inline_xattr_slab instead of per-sb slab cache

As Hong Yun reported in mailing list:

loop7: detected capacity change from 0 to 131072
------------[ cut here ]------------
kmem_cache of name 'f2fs_xattr_entry-7:7' already exists
WARNING: CPU: 0 PID: 24426 at mm/slab_common.c:110 kmem_cache_sanity_check mm/slab_common.c:109 [inline]
WARNING: CPU: 0 PID: 24426 at mm/slab_common.c:110 __kmem_cache_create_args+0xa6/0x320 mm/slab_common.c:307
CPU: 0 UID: 0 PID: 24426 Comm: syz.7.1370 Not tainted 6.17.0-rc4 #1 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:kmem_cache_sanity_check mm/slab_common.c:109 [inline]
RIP: 0010:__kmem_cache_create_args+0xa6/0x320 mm/slab_common.c:307
Call Trace:
 __kmem_cache_create include/linux/slab.h:353 [inline]
 f2fs_kmem_cache_create fs/f2fs/f2fs.h:2943 [inline]
 f2fs_init_xattr_caches+0xa5/0xe0 fs/f2fs/xattr.c:843
 f2fs_fill_super+0x1645/0x2620 fs/f2fs/super.c:4918
 get_tree_bdev_flags+0x1fb/0x260 fs/super.c:1692
 vfs_get_tree+0x43/0x140 fs/super.c:1815
 do_new_mount+0x201/0x550 fs/namespace.c:3808
 do_mount fs/namespace.c:4136 [inline]
 __do_sys_mount fs/namespace.c:4347 [inline]
 __se_sys_mount+0x298/0x2f0 fs/namespace.c:4324
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x8e/0x3a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

The bug can be reproduced w/ below scripts:
- mount /dev/vdb /mnt1
- mount /dev/vdc /mnt2
- umount /mnt1
- mounnt /dev/vdb /mnt1

The reason is if we created two slab caches, named f2fs_xattr_entry-7:3
and f2fs_xattr_entry-7:7, and they have the same slab size. Actually,
slab system will only create one slab cache core structure which has
slab name of "f2fs_xattr_entry-7:3", and two slab caches share the same
structure and cache address.

So, if we destroy f2fs_xattr_entry-7:3 cache w/ cache address, it will
decrease reference count of slab cache, rather than release slab cache
entirely, since there is one more user has referenced the cache.

Then, if we try to create slab cache w/ name "f2fs_xattr_entry-7:3" again,
slab system will find that there is existed cache which has the same name
and trigger the warning.

Let's changes to use global inline_xattr_slab instead of per-sb slab cache
for fixing.

The Linux kernel CVE team has assigned CVE-2025-71105 to this issue.


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

	Issue introduced in 5.7 with commit a999150f4fe3abbb7efd05411fd5b460be699943 and fixed in 6.1.160 with commit 72ce19dfed162da6e430467333b2da70471d08a4
	Issue introduced in 5.7 with commit a999150f4fe3abbb7efd05411fd5b460be699943 and fixed in 6.6.120 with commit be4c3a3c6c2304a8fcd14095d18d26f0cc4e222a
	Issue introduced in 5.7 with commit a999150f4fe3abbb7efd05411fd5b460be699943 and fixed in 6.12.64 with commit 1eb0b130196bcbc56c5c80c83139fa70c0aa82c5
	Issue introduced in 5.7 with commit a999150f4fe3abbb7efd05411fd5b460be699943 and fixed in 6.18.3 with commit e6d828eae00ec192e18c2ddaa2fd32050a96048a
	Issue introduced in 5.7 with commit a999150f4fe3abbb7efd05411fd5b460be699943 and fixed in 6.19-rc1 with commit 1f27ef42bb0b7c0740c5616ec577ec188b8a1d05

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-2025-71105
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/f2fs/f2fs.h
	fs/f2fs/super.c
	fs/f2fs/xattr.c
	fs/f2fs/xattr.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/72ce19dfed162da6e430467333b2da70471d08a4
	https://git.kernel.org/stable/c/be4c3a3c6c2304a8fcd14095d18d26f0cc4e222a
	https://git.kernel.org/stable/c/1eb0b130196bcbc56c5c80c83139fa70c0aa82c5
	https://git.kernel.org/stable/c/e6d828eae00ec192e18c2ddaa2fd32050a96048a
	https://git.kernel.org/stable/c/1f27ef42bb0b7c0740c5616ec577ec188b8a1d05