---
id: CVE-2023-53447
title: 'f2fs: don''t reset unchangable mount option in f2fs_remount()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  f2fs: don't reset unchangable mount option in f2fs_remount()

  syzbot reports a bug as below:

  general protection fault, probably for non-canonical address 0xdffffc00000…
severity: medium
cvss: 4.7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: adp
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 <
    f6464b3c31344af4964443dbbcb4596ac9b46519
  - >-
    Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 <
    115557cc226a927924f2d7d1980ccbf6e3b3bb36
  - >-
    Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 <
    458c15dfbce62c35fefd9ca637b20a051309c9f1
  - Linux 3.8
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-01-14T19:19:57.010722Z'
published: '2025-09-18'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T12:17:30.478Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2023-53447'
references:
  - url: 'https://git.kernel.org/stable/c/f6464b3c31344af4964443dbbcb4596ac9b46519'
  - url: 'https://git.kernel.org/stable/c/115557cc226a927924f2d7d1980ccbf6e3b3bb36'
  - url: 'https://git.kernel.org/stable/c/458c15dfbce62c35fefd9ca637b20a051309c9f1'
tags:
  - cve.org
epss: 0.00108
epssPercentile: 0.01199
ingestedAt: '2026-11-03T11:43:15.786Z'
---

## Overview

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

f2fs: don't reset unchangable mount option in f2fs_remount()

syzbot reports a bug as below:

general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] PREEMPT SMP KASAN
RIP: 0010:__lock_acquire+0x69/0x2000 kernel/locking/lockdep.c:4942
Call Trace:
 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5691
 __raw_write_lock include/linux/rwlock_api_smp.h:209 [inline]
 _raw_write_lock+0x2e/0x40 kernel/locking/spinlock.c:300
 __drop_extent_tree+0x3ac/0x660 fs/f2fs/extent_cache.c:1100
 f2fs_drop_extent_tree+0x17/0x30 fs/f2fs/extent_cache.c:1116
 f2fs_insert_range+0x2d5/0x3c0 fs/f2fs/file.c:1664
 f2fs_fallocate+0x4e4/0x6d0 fs/f2fs/file.c:1838
 vfs_fallocate+0x54b/0x6b0 fs/open.c:324
 ksys_fallocate fs/open.c:347 [inline]
 __do_sys_fallocate fs/open.c:355 [inline]
 __se_sys_fallocate fs/open.c:353 [inline]
 __x64_sys_fallocate+0xbd/0x100 fs/open.c:353
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The root cause is race condition as below:
- since it tries to remount rw filesystem, so that do_remount won't
call sb_prepare_remount_readonly to block fallocate, there may be race
condition in between remount and fallocate.
- in f2fs_remount(), default_options() will reset mount option to default
one, and then update it based on result of parse_options(), so there is
a hole which race condition can happen.

Thread A			Thread B
- f2fs_fill_super
 - parse_options
  - clear_opt(READ_EXTENT_CACHE)

- f2fs_remount
 - default_options
  - set_opt(READ_EXTENT_CACHE)
				- f2fs_fallocate
				 - f2fs_insert_range
				  - f2fs_drop_extent_tree
				   - __drop_extent_tree
				    - __may_extent_tree
				     - test_opt(READ_EXTENT_CACHE) return true
				    - write_lock(&et->lock) access NULL pointer
 - parse_options
  - clear_opt(READ_EXTENT_CACHE)

## Affected

- `Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 < f6464b3c31344af4964443dbbcb4596ac9b46519`
- `Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 < 115557cc226a927924f2d7d1980ccbf6e3b3bb36`
- `Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 < 458c15dfbce62c35fefd9ca637b20a051309c9f1`
- `Linux 3.8`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.