[v6.1] possible deadlock in map_mft_record (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 090666d3cc90 Linux 6.1.177
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11835b39580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f5aae664b2df43c2
dashboard link: https://syzkaller.appspot.com/bug?extid=ebb55fd56e509c27f142
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0b218516a5e9/disk-090666d3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3239ad568bdf/vmlinux-090666d3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a8b19cfbec3e/bzImage-090666d3.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ebb55f...@syzkaller.appspotmail.com

ntfs: volume version 3.1.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.779/6938 is trying to acquire lock:
ffff888071eb8190 (&ni->mrec_lock){+.+.}-{3:3}, at: map_mft_record+0x4c/0x650 fs/ntfs/mft.c:154

but task is already holding lock:
ffff888071eb8100 (&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+0x42/0x2d0 kernel/locking/rwsem.c:1520
ntfs_read_block fs/ntfs/aops.c:248 [inline]
ntfs_read_folio+0x1439/0x2980 fs/ntfs/aops.c:436
filemap_read_folio+0x164/0x7a0 mm/filemap.c:2490
do_read_cache_folio+0x29e/0x790 mm/filemap.c:3659
do_read_cache_page+0x32/0x230 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+0x24e/0x1a90 fs/ntfs/mft.c:480
write_mft_record_nolock+0x1489/0x1990 fs/ntfs/mft.c:805
write_mft_record+0x136/0x310 fs/ntfs/mft.h:95
__ntfs_write_inode+0x6ae/0xbe0 fs/ntfs/inode.c:3050
ntfs_commit_inode fs/ntfs/inode.h:300 [inline]
ntfs_put_super+0xec1/0x1050 fs/ntfs/super.c:2307
generic_shutdown_super+0x130/0x340 fs/super.c:501
kill_block_super+0x7c/0xe0 fs/super.c:1470
deactivate_locked_super+0x93/0xf0 fs/super.c:332
cleanup_mnt+0x471/0x4f0 fs/namespace.c:1191
task_work_run+0x1d0/0x260 kernel/task_work.c:203
exit_task_work include/linux/task_work.h:39 [inline]
do_exit+0x9d5/0x2570 kernel/exit.c:881
do_group_exit+0x229/0x2e0 kernel/exit.c:1024
get_signal+0x1259/0x1340 kernel/signal.c:2872
arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&ni->mrec_lock){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3830 [inline]
__lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063
lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747
map_mft_record+0x4c/0x650 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+0xca0/0xf90 fs/attr.c:499
do_truncate+0x1ac/0x240 fs/open.c:65
handle_truncate fs/namei.c:3293 [inline]
do_open fs/namei.c:3638 [inline]
path_openat+0x2897/0x2f10 fs/namei.c:3791
do_filp_open+0x1ee/0x420 fs/namei.c:3818
do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
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.0.779/6938:
#0: ffff8880520fa460 (sb_writers#16){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402
#1: ffff888071eb8470 (&sb->s_type->i_mutex_key#43){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
#1: ffff888071eb8470 (&sb->s_type->i_mutex_key#43){+.+.}-{3:3}, at: do_truncate+0x198/0x240 fs/open.c:63
#2: ffff888071eb8100 (&rl->lock){++++}-{3:3}, at: ntfs_truncate+0x213/0x2760 fs/ntfs/inode.c:2378

stack backtrace:
CPU: 1 PID: 6938 Comm: syz.0.779 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3830 [inline]
__lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063
lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747
map_mft_record+0x4c/0x650 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+0xca0/0xf90 fs/attr.c:499
do_truncate+0x1ac/0x240 fs/open.c:65
handle_truncate fs/namei.c:3293 [inline]
do_open fs/namei.c:3638 [inline]
path_openat+0x2897/0x2f10 fs/namei.c:3791
do_filp_open+0x1ee/0x420 fs/namei.c:3818
do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
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: 0033:0x7fdf0c59de59
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:00007fdf0d470028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fdf0c825fa0 RCX: 00007fdf0c59de59
RDX: 00000000000a0242 RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007fdf0c633e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdf0c826038 R14: 00007fdf0c825fa0 R15: 00007fff3e8006c8
</TASK>


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