syzbot

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.1.391/6169 is trying to acquire lock:
ffff888053b5f510 (&ni->mrec_lock){+.+.}-{3:3}, at: map_mft_record+0x4c/0x650 fs/ntfs/mft.c:154

but task is already holding lock:
ffff888053b5f480 (&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+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: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+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:1470 [inline]
       __writeback_single_inode+0x75b/0x1160 fs/fs-writeback.c:1687
       writeback_sb_inodes+0xad8/0x17d0 fs/fs-writeback.c:1913
       wb_writeback+0x468/0xd00 fs/fs-writeback.c:2087
       wb_do_writeback fs/fs-writeback.c:2230 [inline]
       wb_workfn+0x435/0xec0 fs/fs-writeback.c:2270
       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_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
       do_iter_readv_writev fs/read_write.c:-1 [inline]
       do_iter_write+0x62d/0xaf0 fs/read_write.c:861
       vfs_writev fs/read_write.c:934 [inline]
       do_pwritev+0x201/0x340 fs/read_write.c:1031
       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.1.391/6169:
 #0: ffff88807bfb4460 (sb_writers#38){.+.+}-{0:0}, at: vfs_writev fs/read_write.c:933 [inline]
 #0: ffff88807bfb4460 (sb_writers#38){.+.+}-{0:0}, at: do_pwritev+0x1ef/0x340 fs/read_write.c:1031
 #1: ffff888053b5f7f0 (&sb->s_type->i_mutex_key#44){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff888053b5f7f0 (&sb->s_type->i_mutex_key#44){+.+.}-{3:3}, at: ntfs_file_write_iter+0x77/0x1a70 fs/ntfs/file.c:1912
 #2: ffff888053b5f480 (&rl->lock){++++}-{3:3}, at: ntfs_attr_extend_allocation+0x520/0x4360 fs/ntfs/attrib.c:2001

stack backtrace:
CPU: 0 PID: 6169 Comm: syz.1.391 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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_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
 do_iter_readv_writev fs/read_write.c:-1 [inline]
 do_iter_write+0x62d/0xaf0 fs/read_write.c:861
 vfs_writev fs/read_write.c:934 [inline]
 do_pwritev+0x201/0x340 fs/read_write.c:1031
 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: 0033:0x7fa153d8f749
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:00007fa154b49038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007fa153fe6090 RCX: 00007fa153d8f749
RDX: 0000000000000001 RSI: 0000200000000100 RDI: 0000000000000004
RBP: 00007fa153e13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000005412 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa153fe6128 R14: 00007fa153fe6090 R15: 00007fff12c90398
 </TASK>