possible deadlock in map_mft_record (2)

Status: upstream: reported on 2026/04/13 05:09
Reported-by: syzbot+089fbfd4971b484153cd@syzkaller.appspotmail.com
First crash: 137d, last: 17d
Similar bugs (10)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 possible deadlock in map_mft_record 4 13 880d 1256d 0/3 auto-obsoleted due to no activity on 2024/07/09 13:58
linux-6.1 possible deadlock in map_mft_record (2) 4 17 203d 713d 0/3 auto-obsoleted due to no activity on 2026/05/18 01:31
upstream possible deadlock in map_mft_record ntfs3 4 syz, C error done 845 940d 1409d 25/29 fixed on 2024/03/20 11:33
linux-4.14 possible deadlock in map_mft_record ntfs 4 syz, C 5 1289d 1383d 0/1 upstream: reported C repro on 2022/11/15 01:41
upstream possible deadlock in map_mft_record (2) fs 4 1 875d 871d 0/29 auto-obsoleted due to no activity on 2024/07/04 04:55
linux-6.6 possible deadlock in map_mft_record (2) 4 2 60d 154d 0/2 upstream: reported on 2026/03/28 01:29
linux-6.1 possible deadlock in map_mft_record (3) 4 2 6d16h 52d 0/3 upstream: reported on 2026/07/07 14:09
linux-5.15 possible deadlock in map_mft_record 4 52 285d 1260d 0/3 auto-obsoleted due to no activity on 2026/02/24 09:06
linux-4.19 possible deadlock in map_mft_record ntfs 4 syz, C error 11 1307d 1419d 0/1 upstream: reported C repro on 2022/10/09 19:52
linux-6.6 possible deadlock in map_mft_record 4 1 257d 257d 0/2 auto-obsoleted due to no activity on 2026/03/24 19:46

Sample crash report:
ntfs: (device loop2): load_and_init_upcase(): Failed to load $UpCase from the volume. Using default.
ntfs: volume version 3.1.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.2.10969/28881 is trying to acquire lock:
ffff8880706ae490 (&ni->mrec_lock){+.+.}-{3:3}, at: map_mft_record+0x4e/0x5f0 fs/ntfs/mft.c:154

but task is already holding lock:
ffff8880706ae400 (&rl->lock){++++}-{3:3}, at: ntfs_truncate+0x213/0x2760 fs/ntfs/inode.c:2378

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&rl->lock){++++}-{3:3}:
       down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
       ntfs_read_block fs/ntfs/aops.c:248 [inline]
       ntfs_readpage+0x1267/0x2140 fs/ntfs/aops.c:435
       do_read_cache_page+0x882/0x1010 mm/filemap.c:-1
       read_mapping_page include/linux/pagemap.h:515 [inline]
       ntfs_map_page+0x24/0x390 fs/ntfs/aops.h:75
       ntfs_sync_mft_mirror+0x251/0x1990 fs/ntfs/mft.c:480
       write_mft_record_nolock+0x1129/0x16e0 fs/ntfs/mft.c:787
       write_mft_record fs/ntfs/mft.h:95 [inline]
       __ntfs_write_inode+0x79c/0xda0 fs/ntfs/inode.c:3050
       write_inode fs/fs-writeback.c:1505 [inline]
       __writeback_single_inode+0x6c4/0xda0 fs/fs-writeback.c:1715
       writeback_sb_inodes+0xaaa/0x1750 fs/fs-writeback.c:1940
       wb_writeback+0x44a/0xbc0 fs/fs-writeback.c:2114
       wb_do_writeback fs/fs-writeback.c:2257 [inline]
       wb_workfn+0x43a/0xf20 fs/fs-writeback.c:2298
       process_one_work+0x867/0xff0 kernel/workqueue.c:2310
       worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
       kthread+0x42e/0x520 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #0 (&ni->mrec_lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012
       lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       map_mft_record+0x4e/0x5f0 fs/ntfs/mft.c:154
       ntfs_truncate+0x286/0x2760 fs/ntfs/inode.c:2383
       ntfs_truncate_vfs fs/ntfs/inode.c:2862 [inline]
       ntfs_setattr+0x2b6/0x390 fs/ntfs/inode.c:2914
       notify_change+0xbc6/0xee0 fs/attr.c:505
       do_truncate+0x1ac/0x240 fs/open.c:65
       vfs_truncate+0x262/0x2f0 fs/open.c:111
       do_sys_truncate+0xf2/0x1c0 fs/open.c:134
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&rl->lock);
                               lock(&ni->mrec_lock);
                               lock(&rl->lock);
  lock(&ni->mrec_lock);

 *** DEADLOCK ***

3 locks held by syz.2.10969/28881:
 #0: ffff88807764e460 (sb_writers#31){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
 #1: ffff8880706ae770 (&sb->s_type->i_mutex_key#38){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff8880706ae770 (&sb->s_type->i_mutex_key#38){+.+.}-{3:3}, at: do_truncate+0x198/0x240 fs/open.c:63
 #2: ffff8880706ae400 (&rl->lock){++++}-{3:3}, at: ntfs_truncate+0x213/0x2760 fs/ntfs/inode.c:2378

stack backtrace:
CPU: 0 PID: 28881 Comm: syz.2.10969 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 map_mft_record+0x4e/0x5f0 fs/ntfs/mft.c:154
 ntfs_truncate+0x286/0x2760 fs/ntfs/inode.c:2383
 ntfs_truncate_vfs fs/ntfs/inode.c:2862 [inline]
 ntfs_setattr+0x2b6/0x390 fs/ntfs/inode.c:2914
 notify_change+0xbc6/0xee0 fs/attr.c:505
 do_truncate+0x1ac/0x240 fs/open.c:65
 vfs_truncate+0x262/0x2f0 fs/open.c:111
 do_sys_truncate+0xf2/0x1c0 fs/open.c:134
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7ff616aac0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff614d04028 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007ff616d33fa0 RCX: 00007ff616aac0d9
RDX: 0000000000000000 RSI: 0000000000002800 RDI: 0000200000000180
RBP: 00007ff616b43024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff616d34038 R14: 00007ff616d33fa0 R15: 00007ffed0b3c6a8
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/11 13:19 linux-5.15.y aabd761612db 71790083 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in map_mft_record
2026/07/09 12:15 linux-5.15.y c86c4726e7f0 a0c310a3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in map_mft_record
2026/04/13 05:08 linux-5.15.y 91d48252ad4b 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in map_mft_record
* Struck through repros no longer work on HEAD.