syzbot

loop5: detected capacity change from 0 to 4096
ntfs: volume version 3.1.
======================================================
WARNING: possible circular locking dependency detected
6.1.140-syzkaller #0 Not tainted
------------------------------------------------------
syz.5.1128/9490 is trying to acquire lock:
ffff888072789210 (&ni->mrec_lock){+.+.}-{3:3}, at: map_mft_record+0x4c/0x650 fs/ntfs/mft.c:154

but task is already holding lock:
ffff888072789180 (&rl->lock){++++}-{3:3}, at: ntfs_truncate+0x20e/0x27c0 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+0x1446/0x2980 fs/ntfs/aops.c:436
       filemap_read_folio+0x160/0x760 mm/filemap.c:2490
       do_read_cache_folio+0x2a0/0x760 mm/filemap.c:3627
       do_read_cache_page+0x32/0x220 mm/filemap.c:3669
       read_mapping_page include/linux/pagemap.h:791 [inline]
       ntfs_map_page fs/ntfs/aops.h:75 [inline]
       ntfs_sync_mft_mirror+0x232/0x1aa0 fs/ntfs/mft.c:480
       write_mft_record_nolock+0x116b/0x18c0 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:1460 [inline]
       __writeback_single_inode+0x75b/0x1160 fs/fs-writeback.c:1677
       writeback_sb_inodes+0xad8/0x17d0 fs/fs-writeback.c:1903
       wb_writeback+0x468/0xd00 fs/fs-writeback.c:2077
       wb_do_writeback fs/fs-writeback.c:2220 [inline]
       wb_workfn+0x435/0xec0 fs/fs-writeback.c:2260
       process_one_work+0x898/0x1160 kernel/workqueue.c:2292
       worker_thread+0xaa2/0x1250 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+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
       lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
       map_mft_record+0x4c/0x650 fs/ntfs/mft.c:154
       ntfs_truncate+0x280/0x27c0 fs/ntfs/inode.c:2383
       ntfs_truncate_vfs fs/ntfs/inode.c:2862 [inline]
       ntfs_setattr+0x2bc/0x3a0 fs/ntfs/inode.c:2914
       notify_change+0xc74/0xf40 fs/attr.c:499
       do_truncate+0x197/0x220 fs/open.c:65
       vfs_truncate+0x262/0x2f0 fs/open.c:111
       do_sys_truncate+0xdc/0x190 fs/open.c:134
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       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.5.1128/9490:
 #0: ffff888076e74460 (sb_writers#32){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:393
 #1: ffff8880727894f0 (&sb->s_type->i_mutex_key#44){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff8880727894f0 (&sb->s_type->i_mutex_key#44){+.+.}-{3:3}, at: do_truncate+0x183/0x220 fs/open.c:63
 #2: ffff888072789180 (&rl->lock){++++}-{3:3}, at: ntfs_truncate+0x20e/0x27c0 fs/ntfs/inode.c:2378

stack backtrace:
CPU: 0 PID: 9490 Comm: syz.5.1128 Not tainted 6.1.140-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 check_noncircular+0x274/0x310 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+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
 map_mft_record+0x4c/0x650 fs/ntfs/mft.c:154
 ntfs_truncate+0x280/0x27c0 fs/ntfs/inode.c:2383
 ntfs_truncate_vfs fs/ntfs/inode.c:2862 [inline]
 ntfs_setattr+0x2bc/0x3a0 fs/ntfs/inode.c:2914
 notify_change+0xc74/0xf40 fs/attr.c:499
 do_truncate+0x197/0x220 fs/open.c:65
 vfs_truncate+0x262/0x2f0 fs/open.c:111
 do_sys_truncate+0xdc/0x190 fs/open.c:134
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8f96b8e969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8f97ae4038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f8f96db5fa0 RCX: 00007f8f96b8e969
RDX: 0000000000000000 RSI: 0000000003000000 RDI: 0000200000000900
RBP: 00007f8f96c10ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f8f96db5fa0 R15: 00007fffdcde95c8
 </TASK>