CVE-2025-71065

None

CVSS

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EPSS

0.2%

Published

Jan 13, 2026

CISA due date

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Cloudanix analysis

Schedule a fix SSVC: Track

A flaw in the Linux kernel's f2fs file system could cause the whole system to freeze under certain memory and file operation conditions.

Exploitation: Local Privilege
Attacker needs: Local User
Complexity: Moderate
Impact: Denial Of Service
Component: OS kernel
Class: Race Condition
Remediation: Upgrade
Effort: Medium
Patch risk: Low

What it actually does

Potential deadlock in f2fs between fs_reclaim, sb_internal, cp_rwsem, and f2fs_lock_op during inode eviction and truncation under memory pressure from kswapd.

Why it matters to the business

Linux systems using f2fs may experience kernel hangs or unresponsiveness during memory reclamation combined with file operations, leading to service disruption and requiring reboots.

How an attack unfolds

An attacker or workload triggers memory pressure to activate kswapd, which attempts inode eviction in f2fs while concurrent operations hold conflicting locks in reverse order, causing deadlock; no named threat actors or ransomware use reported.

How to fix it

Update the Linux kernel to the fixed commit 8bd6dff8b801abaa362272894bda795bf0cf1307 or later stable release containing the f2fs deadlock fix.

How to confirm the fix worked

Confirm kernel version includes commit 8bd6dff8b801abaa362272894bda795bf0cf1307; run f2fs-specific stress tests involving eviction under memory pressure to verify absence of deadlock.

Typical attack path

Trigger memory pressure to invoke kswapd and shrinker paths
Perform f2fs file truncation or atomic write operations that acquire cp_rwsem or f2fs_lock_op
Force inode eviction via iput or prune_icache while sb_internal is held
Reach circular lock acquisition resulting in deadlock

How to detect it

Review kernel logs for circular locking dependency warnings, hung task traces involving kswapd and f2fs_evict_inode, or stack traces referencing cp_rwsem and sb_internal.

What your security team should do

Prioritize kernel upgrade on all f2fs deployments within standard patch windows
Monitor for f2fs-related kernel oops or hung task warnings in logs
Test upgraded kernels in staging environments before broad rollout

The record

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to avoid potential deadlock As Jiaming Zhang and syzbot reported, there is potential deadlock in f2fs as below: Chain exists of: &sbi->cp_rwsem --> fs_reclaim --> sb_internal#2 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(sb_internal#2); lock(fs_reclaim); lock(sb_internal#2); rlock(&sbi->cp_rwsem); *** DEADLOCK *** 3 locks held by kswapd0/73: #0: ffffffff8e247a40 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:7015 [inline] #0: ffffffff8e247a40 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x951/0x2800 mm/vmscan.c:7389 #1: ffff8880118400e0 (&type->s_umount_key#50){.+.+}-{4:4}, at: super_trylock_shared fs/super.c:562 [inline] #1: ffff8880118400e0 (&type->s_umount_key#50){.+.+}-{4:4}, at: super_cache_scan+0x91/0x4b0 fs/super.c:197 #2: ffff888011840610 (sb_internal#2){.+.+}-{0:0}, at: f2fs_evict_inode+0x8d9/0x1b60 fs/f2fs/inode.c:890 stack backtrace: CPU: 0 UID: 0 PID: 73 Comm: kswapd0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_read+0x46/0x2e0 kernel/locking/rwsem.c:1537 f2fs_down_read fs/f2fs/f2fs.h:2278 [inline] f2fs_lock_op fs/f2fs/f2fs.h:2357 [inline] f2fs_do_truncate_blocks+0x21c/0x10c0 fs/f2fs/file.c:791 f2fs_truncate_blocks+0x10a/0x300 fs/f2fs/file.c:867 f2fs_truncate+0x489/0x7c0 fs/f2fs/file.c:925 f2fs_evict_inode+0x9f2/0x1b60 fs/f2fs/inode.c:897 evict+0x504/0x9c0 fs/inode.c:810 f2fs_evict_inode+0x1dc/0x1b60 fs/f2fs/inode.c:853 evict+0x504/0x9c0 fs/inode.c:810 dispose_list fs/inode.c:852 [inline] prune_icache_sb+0x21b/0x2c0 fs/inode.c:1000 super_cache_scan+0x39b/0x4b0 fs/super.c:224 do_shrink_slab+0x6ef/0x1110 mm/shrinker.c:437 shrink_slab_memcg mm/shrinker.c:550 [inline] shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628 shrink_one+0x28a/0x7c0 mm/vmscan.c:4955 shrink_many mm/vmscan.c:5016 [inline] lru_gen_shrink_node mm/vmscan.c:5094 [inline] shrink_node+0x315d/0x3780 mm/vmscan.c:6081 kswapd_shrink_node mm/vmscan.c:6941 [inline] balance_pgdat mm/vmscan.c:7124 [inline] kswapd+0x147c/0x2800 mm/vmscan.c:7389 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK> The root cause is deadlock among four locks as below: kswapd - fs_reclaim --- Lock A - shrink_one - evict - f2fs_evict_inode - sb_start_intwrite --- Lock B - iput - evict - f2fs_evict_inode - sb_start_intwrite --- Lock B - f2fs_truncate - f2fs_truncate_blocks - f2fs_do_truncate_blocks - f2fs_lock_op --- Lock C ioctl - f2fs_ioc_commit_atomic_write - f2fs_lock_op --- Lock C - __f2fs_commit_atomic_write - __replace_atomic_write_block - f2fs_get_dnode_of_data - __get_node_folio - f2fs_check_nid_range - f2fs_handle_error - f2fs_record_errors - f2fs_down_write --- Lock D open - do_open - do_truncate - security_inode_need_killpriv - f2fs_getxattr - lookup_all_xattrs - f2fs_handle_error - f2fs_record_errors - f2fs_down_write --- Lock D - f2fs_commit_super - read_mapping_folio - filemap_alloc_folio_noprof - prepare_alloc_pages - fs_reclaim_acquire --- Lock A In order to a ---truncated---

Affected packages

Ecosystem	Package	Introduced	Fixed
Linux	Kernel	6.1.0	6.6.120
Mageia:9	kernel	0	6.6.120-1.mga9
Mageia:9	kernel-linus	0	6.6.120-1.mga9
Mageia:9	kmod-virtualbox	0	7.1.14-14.mga9
Mageia:9	kmod-xtables-addons	0	3.24-88.mga9