linux-cve-announce - CVE-2023-54253: btrfs: set page extent mapped after read_folio in relocate_one

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <2025123055-CVE-2023-54253-18d1@gregkh>
Date: Tue, 30 Dec 2025 13:20:19 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-54253: btrfs: set page extent mapped after read_folio in relocate_one_page

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

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

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

btrfs: set page extent mapped after read_folio in relocate_one_page

One of the CI runs triggered the following panic

  assertion failed: PagePrivate(page) && page->private, in fs/btrfs/subpage.c:229
  ------------[ cut here ]------------
  kernel BUG at fs/btrfs/subpage.c:229!
  Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
  CPU: 0 PID: 923660 Comm: btrfs Not tainted 6.5.0-rc3+ #1
  pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
  pc : btrfs_subpage_assert+0xbc/0xf0
  lr : btrfs_subpage_assert+0xbc/0xf0
  sp : ffff800093213720
  x29: ffff800093213720 x28: ffff8000932138b4 x27: 000000000c280000
  x26: 00000001b5d00000 x25: 000000000c281000 x24: 000000000c281fff
  x23: 0000000000001000 x22: 0000000000000000 x21: ffffff42b95bf880
  x20: ffff42b9528e0000 x19: 0000000000001000 x18: ffffffffffffffff
  x17: 667274622f736620 x16: 6e69202c65746176 x15: 0000000000000028
  x14: 0000000000000003 x13: 00000000002672d7 x12: 0000000000000000
  x11: ffffcd3f0ccd9204 x10: ffffcd3f0554ae50 x9 : ffffcd3f0379528c
  x8 : ffff800093213428 x7 : 0000000000000000 x6 : ffffcd3f091771e8
  x5 : ffff42b97f333948 x4 : 0000000000000000 x3 : 0000000000000000
  x2 : 0000000000000000 x1 : ffff42b9556cde80 x0 : 000000000000004f
  Call trace:
   btrfs_subpage_assert+0xbc/0xf0
   btrfs_subpage_set_dirty+0x38/0xa0
   btrfs_page_set_dirty+0x58/0x88
   relocate_one_page+0x204/0x5f0
   relocate_file_extent_cluster+0x11c/0x180
   relocate_data_extent+0xd0/0xf8
   relocate_block_group+0x3d0/0x4e8
   btrfs_relocate_block_group+0x2d8/0x490
   btrfs_relocate_chunk+0x54/0x1a8
   btrfs_balance+0x7f4/0x1150
   btrfs_ioctl+0x10f0/0x20b8
   __arm64_sys_ioctl+0x120/0x11d8
   invoke_syscall.constprop.0+0x80/0xd8
   do_el0_svc+0x6c/0x158
   el0_svc+0x50/0x1b0
   el0t_64_sync_handler+0x120/0x130
   el0t_64_sync+0x194/0x198
  Code: 91098021 b0007fa0 91346000 97e9c6d2 (d4210000)

This is the same problem outlined in 17b17fcd6d44 ("btrfs:
set_page_extent_mapped after read_folio in btrfs_cont_expand") , and the
fix is the same.  I originally looked for the same pattern elsewhere in
our code, but mistakenly skipped over this code because I saw the page
cache readahead before we set_page_extent_mapped, not realizing that
this was only in the !page case, that we can still end up with a
!uptodate page and then do the btrfs_read_folio further down.

The fix here is the same as the above mentioned patch, move the
set_page_extent_mapped call to after the btrfs_read_folio() block to
make sure that we have the subpage blocksize stuff setup properly before
using the page.

The Linux kernel CVE team has assigned CVE-2023-54253 to this issue.


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

	Fixed in 6.1.54 with commit 08daa38ca212d87f77beae839bc9be71079c7abf
	Fixed in 6.5.4 with commit 9d1e020ed9649cf140fcfafd052cfdcce9e9d67d
	Fixed in 6.6 with commit e7f1326cc24e22b38afc3acd328480a1183f9e79

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-2023-54253
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/btrfs/relocation.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/08daa38ca212d87f77beae839bc9be71079c7abf
	https://git.kernel.org/stable/c/9d1e020ed9649cf140fcfafd052cfdcce9e9d67d
	https://git.kernel.org/stable/c/e7f1326cc24e22b38afc3acd328480a1183f9e79