CVE-2025-23132 f2fs: quota: fix to avoid warning in dquot_writeback_dquots()
A race condition in the Linux kernel F2FS filesystem can trigger a kernel warning, potentially leading to a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-23132?
CVE-2025-23132 is a high-severity vulnerability in Linux kernel, published on 16 Apr 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
f2fs: quota: fix to avoid warning in dquot_writeback_dquots()
F2FS-fs (dm-59): checkpoint=enable has some unwritten data.
------------[ cut here ]------------ WARNING: CPU: 6 PID: 8013 at fs/quota/dquot.c:691 dquot_writeback_dquots+0x2fc/0x308 pc : dquot_writeback_dquots+0x2fc/0x308 lr : f2fs_quota_sync+0xcc/0x1c4 Call trace: dquot_writeback_dquots+0x2fc/0x308 f2fs_quota_sync+0xcc/0x1c4 f2fs_write_checkpoint+0x3d4/0x9b0 f2fs_issue_checkpoint+0x1bc/0x2c0 f2fs_sync_fs+0x54/0x150 f2fs_do_sync_file+0x2f8/0x814 __f2fs_ioctl+0x1960/0x3244 f2fs_ioctl+0x54/0xe0 __arm64_sys_ioctl+0xa8/0xe4 invoke_syscall+0x58/0x114
checkpoint and f2fs_remount may race as below, resulting triggering warning in dquot_writeback_dquots().
atomic write remount - do_remount - down_write(&sb->s_umount); - f2fs_remount - ioctl - f2fs_do_sync_file - f2fs_sync_fs - f2fs_write_checkpoint - block_operations - locked = down_read_trylock(&sbi->sb->s_umount) : fail to lock due to the write lock was held by remount - up_write(&sb->s_umount); - f2fs_quota_sync - dquot_writeback_dquots - WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount)) : trigger warning because s_umount lock was unlocked by remount
If checkpoint comes from mount/umount/remount/freeze/quotactl, caller of checkpoint has already held s_umount lock, calling dquot_writeback_dquots() in the context should be safe.
So let's record task to sbi->umount_lock_holder, so that checkpoint can know whether the lock has held in the context or not by checking current w/ it.
In addition, in order to not misrepresent caller of checkpoint, we should not allow to trigger async checkpoint for those callers: mount/umount/remount/ freeze/quotactl.
Which versions are affected by CVE-2025-23132?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-23132?
Apply the vendor's patch.
Is CVE-2025-23132 being exploited?
There is no known exploitation of CVE-2025-23132 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-23132, DEBIAN-CVE-2025-23132, GHSA-v4w6-p754-7g2j, ROOT-OS-DEBIAN-11-CVE-2025-23132, ROOT-OS-DEBIAN-12-CVE-2025-23132, ROOT-OS-DEBIAN-13-CVE-2025-23132 and 3 more.