syzbot


possible deadlock in map_mft_record (2)

Status: upstream: reported on 2024/09/14 09:25
Reported-by: syzbot+ba30c43520c2fdcee3a2@syzkaller.appspotmail.com
First crash: 502d, last: 1d06h
Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 possible deadlock in map_mft_record 4 13 669d 1044d 0/3 auto-obsoleted due to no activity on 2024/07/09 13:58
upstream possible deadlock in map_mft_record ntfs3 4 C error done 845 729d 1198d 25/29 fixed on 2024/03/20 11:33
linux-4.14 possible deadlock in map_mft_record ntfs 4 C 5 1077d 1171d 0/1 upstream: reported C repro on 2022/11/15 01:41
upstream possible deadlock in map_mft_record (2) fs 4 1 664d 660d 0/29 auto-obsoleted due to no activity on 2024/07/04 04:55
linux-5.15 possible deadlock in map_mft_record 4 52 74d 1049d 0/3 upstream: reported on 2023/03/17 18:38
linux-4.19 possible deadlock in map_mft_record ntfs 4 C error 11 1096d 1207d 0/1 upstream: reported C repro on 2022/10/09 19:52
linux-6.6 possible deadlock in map_mft_record 4 1 45d 45d 0/2 upstream: reported on 2025/12/14 19:45

Sample crash report:
ntfs: volume version 3.1.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.5.2441/11600 is trying to acquire lock:
ffff88804f49d410 (&ni->mrec_lock){+.+.}-{3:3}, at: map_mft_record+0x4c/0x650 fs/ntfs/mft.c:154

but task is already holding lock:
ffff88804f49d380 (&rl->lock){++++}-{3:3}, at: ntfs_attr_extend_allocation+0x520/0x4360 fs/ntfs/attrib.c:2001

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&rl->lock){++++}-{3:3}:
       down_read+0x42/0x2d0 kernel/locking/rwsem.c:1520
       ntfs_read_block fs/ntfs/aops.c:248 [inline]
       ntfs_read_folio+0x1463/0x29c0 fs/ntfs/aops.c:436
       filemap_read_folio+0x16b/0x770 mm/filemap.c:2490
       do_read_cache_folio+0x2a0/0x760 mm/filemap.c:3659
       do_read_cache_page+0x32/0x220 mm/filemap.c:3701
       read_mapping_page include/linux/pagemap.h:793 [inline]
       ntfs_map_page fs/ntfs/aops.h:75 [inline]
       ntfs_sync_mft_mirror+0x24f/0x1ad0 fs/ntfs/mft.c:480
       write_mft_record_nolock+0x1188/0x1900 fs/ntfs/mft.c:787
       write_mft_record+0x136/0x300 fs/ntfs/mft.h:95
       __ntfs_write_inode+0x724/0xbf0 fs/ntfs/inode.c:3050
       write_inode fs/fs-writeback.c:1470 [inline]
       __writeback_single_inode+0x75b/0x1160 fs/fs-writeback.c:1687
       writeback_sb_inodes+0xb30/0x1850 fs/fs-writeback.c:1913
       wb_writeback+0x482/0xd50 fs/fs-writeback.c:2087
       wb_do_writeback fs/fs-writeback.c:2230 [inline]
       wb_workfn+0x423/0xee0 fs/fs-writeback.c:2270
       process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
       worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
       kthread+0x29d/0x330 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

-> #0 (&ni->mrec_lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x2d07/0x7d10 kernel/locking/lockdep.c:5049
       lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x12d/0xaf0 kernel/locking/mutex.c:747
       map_mft_record+0x4c/0x650 fs/ntfs/mft.c:154
       ntfs_attr_extend_allocation+0x528/0x4360 fs/ntfs/attrib.c:2002
       ntfs_prepare_file_for_write fs/ntfs/file.c:391 [inline]
       ntfs_file_write_iter+0x369/0x1a70 fs/ntfs/file.c:1915
       call_write_iter include/linux/fs.h:2265 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x4b1/0xa30 fs/read_write.c:584
       ksys_pwrite64 fs/read_write.c:699 [inline]
       __do_sys_pwrite64 fs/read_write.c:709 [inline]
       __se_sys_pwrite64 fs/read_write.c:706 [inline]
       __x64_sys_pwrite64+0x197/0x220 fs/read_write.c:706
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

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.5.2441/11600:
 #0: ffff88807c6be460 (sb_writers#42){.+.+}-{0:0}, at: vfs_write+0x26b/0xa30 fs/read_write.c:580
 #1: ffff88804f49d6f0 (&sb->s_type->i_mutex_key#48){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff88804f49d6f0 (&sb->s_type->i_mutex_key#48){+.+.}-{3:3}, at: ntfs_file_write_iter+0x77/0x1a70 fs/ntfs/file.c:1912
 #2: ffff88804f49d380 (&rl->lock){++++}-{3:3}, at: ntfs_attr_extend_allocation+0x520/0x4360 fs/ntfs/attrib.c:2001

stack backtrace:
CPU: 0 PID: 11600 Comm: syz.5.2441 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x2d07/0x7d10 kernel/locking/lockdep.c:5049
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x12d/0xaf0 kernel/locking/mutex.c:747
 map_mft_record+0x4c/0x650 fs/ntfs/mft.c:154
 ntfs_attr_extend_allocation+0x528/0x4360 fs/ntfs/attrib.c:2002
 ntfs_prepare_file_for_write fs/ntfs/file.c:391 [inline]
 ntfs_file_write_iter+0x369/0x1a70 fs/ntfs/file.c:1915
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x4b1/0xa30 fs/read_write.c:584
 ksys_pwrite64 fs/read_write.c:699 [inline]
 __do_sys_pwrite64 fs/read_write.c:709 [inline]
 __se_sys_pwrite64 fs/read_write.c:706 [inline]
 __x64_sys_pwrite64+0x197/0x220 fs/read_write.c:706
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f7f1039aeb9
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:00007f7f11269028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f7f10615fa0 RCX: 00007f7f1039aeb9
RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000004
RBP: 00007f7f10408c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000e7c R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7f10616038 R14: 00007f7f10615fa0 R15: 00007ffda4aec388
 </TASK>
ntfs: (device loop5): ntfs_cluster_alloc(): Failed to map page.
ntfs: (device loop5): ntfs_cluster_alloc(): Failed to allocate clusters, aborting (error -4).
ntfs: (device loop5): ntfs_attr_extend_allocation(): Cannot extend allocation of inode 0x43, attribute type 0x80, because the conversion from resident to non-resident attribute failed with error code -4.
ntfs: (device loop5): ntfs_prepare_file_for_write(): Cannot perform write to inode 0x43, attribute type 0x80, because extending the allocation failed (error 5).

Crashes (16):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/28 12:23 linux-6.1.y cd9b81672742 004c195c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in map_mft_record
2025/12/21 19:49 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in map_mft_record
2025/12/14 19:52 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in map_mft_record
2025/07/05 07:30 linux-6.1.y 7e69c33e4858 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in map_mft_record
2025/06/18 14:53 linux-6.1.y 58485ff1a74f ed3e87f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in map_mft_record
2025/06/01 12:18 linux-6.1.y da3c5173c55f 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in map_mft_record
2025/02/14 02:26 linux-6.1.y 0cbb5f65e52f d9a046cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in map_mft_record
2025/11/12 07:17 linux-6.1.y f6e38ae624cf 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in map_mft_record
2025/10/24 10:05 linux-6.1.y 8e6e2188d949 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in map_mft_record
2025/09/15 20:32 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in map_mft_record
2025/09/14 08:49 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in map_mft_record
2025/08/10 18:06 linux-6.1.y 3594f306da12 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in map_mft_record
2025/08/05 22:57 linux-6.1.y 3594f306da12 ffe1dd46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in map_mft_record
2025/05/01 18:26 linux-6.1.y 535ec20c5027 51b137cd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in map_mft_record
2024/12/11 13:38 linux-6.1.y e4d90d63d385 ff949d25 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in map_mft_record
2024/09/14 09:24 linux-6.1.y 5f55cad62cc9 c7e35043 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in map_mft_record
* Struck through repros no longer work on HEAD.