syzbot

======================================================
WARNING: possible circular locking dependency detected
6.8.0-rc2-syzkaller-00043-g2a6526c4f389 #0 Not tainted
------------------------------------------------------
kworker/u4:7/1093 is trying to acquire lock:
ffff888076e499c0 (&rl->lock){++++}-{3:3}, at: ntfs_read_block fs/ntfs/aops.c:242 [inline]
ffff888076e499c0 (&rl->lock){++++}-{3:3}, at: ntfs_read_folio+0x1308/0x23e0 fs/ntfs/aops.c:430

but task is already holding lock:
ffff888076e4d410 (&ni->mrec_lock){+.+.}-{3:3}, at: map_mft_record+0x4c/0x630 fs/ntfs/mft.c:154

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ni->mrec_lock){+.+.}-{3:3}:
       lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd60 kernel/locking/mutex.c:752
       map_mft_record+0x4c/0x630 fs/ntfs/mft.c:154
       ntfs_truncate+0x267/0x2880 fs/ntfs/inode.c:2383
       ntfs_truncate_vfs fs/ntfs/inode.c:2864 [inline]
       ntfs_setattr+0x3f5/0x4d0 fs/ntfs/inode.c:2916
       notify_change+0xb99/0xe60 fs/attr.c:499
       do_truncate+0x220/0x300 fs/open.c:66
       handle_truncate fs/namei.c:3299 [inline]
       do_open fs/namei.c:3645 [inline]
       path_openat+0x29c1/0x31e0 fs/namei.c:3798
       do_filp_open+0x234/0x490 fs/namei.c:3825
       do_sys_openat2+0x13e/0x1d0 fs/open.c:1404
       do_sys_open fs/open.c:1419 [inline]
       __do_sys_openat fs/open.c:1435 [inline]
       __se_sys_openat fs/open.c:1430 [inline]
       __x64_sys_openat+0x247/0x290 fs/open.c:1430
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x63/0x6b

-> #0 (&rl->lock){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain+0x1909/0x5ab0 kernel/locking/lockdep.c:3869
       __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137
       lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754
       down_read+0xb1/0xa40 kernel/locking/rwsem.c:1526
       ntfs_read_block fs/ntfs/aops.c:242 [inline]
       ntfs_read_folio+0x1308/0x23e0 fs/ntfs/aops.c:430
       filemap_read_folio+0x19c/0x780 mm/filemap.c:2324
       do_read_cache_folio+0x134/0x810 mm/filemap.c:3703
       do_read_cache_page+0x30/0x200 mm/filemap.c:3769
       read_mapping_page include/linux/pagemap.h:888 [inline]
       ntfs_map_page fs/ntfs/aops.h:75 [inline]
       ntfs_sync_mft_mirror+0x25f/0x1ae0 fs/ntfs/mft.c:480
       write_mft_record_nolock+0x1155/0x18f0 fs/ntfs/mft.c:787
       write_mft_record+0x149/0x310 fs/ntfs/mft.h:95
       __ntfs_write_inode+0x703/0xbb0 fs/ntfs/inode.c:3052
       write_inode fs/fs-writeback.c:1473 [inline]
       __writeback_single_inode+0x69b/0xfc0 fs/fs-writeback.c:1690
       writeback_sb_inodes+0x8e3/0x1220 fs/fs-writeback.c:1916
       __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:1987
       wb_writeback+0x461/0xc70 fs/fs-writeback.c:2094
       wb_check_background_flush fs/fs-writeback.c:2164 [inline]
       wb_do_writeback fs/fs-writeback.c:2252 [inline]
       wb_workfn+0xc33/0xfb0 fs/fs-writeback.c:2279
       process_one_work kernel/workqueue.c:2633 [inline]
       process_scheduled_works+0x90f/0x1420 kernel/workqueue.c:2706
       worker_thread+0xa5f/0x1000 kernel/workqueue.c:2787
       kthread+0x2d3/0x370 kernel/kthread.c:388
       ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

other info that might help us debug this:

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

4 locks held by kworker/u4:7/1093:
 #0: ffff8880176d9d38 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2608 [inline]
 #0: ffff8880176d9d38 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x1420 kernel/workqueue.c:2706
 #1: ffffc9000475fd20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2608 [inline]
 #1: ffffc9000475fd20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x1420 kernel/workqueue.c:2706
 #2: ffff8880298800e0 (&type->s_umount_key#63){.+.+}-{3:3}, at: super_trylock_shared+0x22/0xf0 fs/super.c:566
 #3: ffff888076e4d410 (&ni->mrec_lock){+.+.}-{3:3}, at: map_mft_record+0x4c/0x630 fs/ntfs/mft.c:154

stack backtrace:
CPU: 1 PID: 1093 Comm: kworker/u4:7 Not tainted 6.8.0-rc2-syzkaller-00043-g2a6526c4f389 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Workqueue: writeback wb_workfn (flush-7:4)
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x366/0x490 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain+0x1909/0x5ab0 kernel/locking/lockdep.c:3869
 __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754
 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1526
 ntfs_read_block fs/ntfs/aops.c:242 [inline]
 ntfs_read_folio+0x1308/0x23e0 fs/ntfs/aops.c:430
 filemap_read_folio+0x19c/0x780 mm/filemap.c:2324
 do_read_cache_folio+0x134/0x810 mm/filemap.c:3703
 do_read_cache_page+0x30/0x200 mm/filemap.c:3769
 read_mapping_page include/linux/pagemap.h:888 [inline]
 ntfs_map_page fs/ntfs/aops.h:75 [inline]
 ntfs_sync_mft_mirror+0x25f/0x1ae0 fs/ntfs/mft.c:480
 write_mft_record_nolock+0x1155/0x18f0 fs/ntfs/mft.c:787
 write_mft_record+0x149/0x310 fs/ntfs/mft.h:95
 __ntfs_write_inode+0x703/0xbb0 fs/ntfs/inode.c:3052
 write_inode fs/fs-writeback.c:1473 [inline]
 __writeback_single_inode+0x69b/0xfc0 fs/fs-writeback.c:1690
 writeback_sb_inodes+0x8e3/0x1220 fs/fs-writeback.c:1916
 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:1987
 wb_writeback+0x461/0xc70 fs/fs-writeback.c:2094
 wb_check_background_flush fs/fs-writeback.c:2164 [inline]
 wb_do_writeback fs/fs-writeback.c:2252 [inline]
 wb_workfn+0xc33/0xfb0 fs/fs-writeback.c:2279
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x90f/0x1420 kernel/workqueue.c:2706
 worker_thread+0xa5f/0x1000 kernel/workqueue.c:2787
 kthread+0x2d3/0x370 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
 </TASK>