syzbot

IPVS: ftp: loaded support on port[0] = 21
ntfs: volume version 3.1.
syz-executor293 (8100): drop_caches: 1
syz-executor293 (8100): drop_caches: 1
======================================================
WARNING: possible circular locking dependency detected
4.19.211-syzkaller #0 Not tainted
------------------------------------------------------
kworker/u4:0/7 is trying to acquire lock:
00000000e1f3a370 (&rl->lock){++++}, at: ntfs_read_block fs/ntfs/aops.c:265 [inline]
00000000e1f3a370 (&rl->lock){++++}, at: ntfs_readpage+0x1909/0x21b0 fs/ntfs/aops.c:452

but task is already holding lock:
0000000010cc17e8 (&ni->mrec_lock){+.+.}, at: map_mft_record+0x3c/0xc70 fs/ntfs/mft.c:168

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ni->mrec_lock){+.+.}:
       map_mft_record+0x3c/0xc70 fs/ntfs/mft.c:168
       ntfs_truncate+0x202/0x2820 fs/ntfs/inode.c:2395
       ntfs_truncate_vfs fs/ntfs/inode.c:2875 [inline]
       ntfs_setattr+0x1b6/0x620 fs/ntfs/inode.c:2925
       notify_change+0x70b/0xfc0 fs/attr.c:334
       do_truncate+0x134/0x1f0 fs/open.c:63
       handle_truncate fs/namei.c:3009 [inline]
       do_last fs/namei.c:3427 [inline]
       path_openat+0x2308/0x2df0 fs/namei.c:3537
       do_filp_open+0x18c/0x3f0 fs/namei.c:3567
       do_sys_open+0x3b3/0x520 fs/open.c:1085
       do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 (&rl->lock){++++}:
       down_read+0x36/0x80 kernel/locking/rwsem.c:24
       ntfs_read_block fs/ntfs/aops.c:265 [inline]
       ntfs_readpage+0x1909/0x21b0 fs/ntfs/aops.c:452
       do_read_cache_page+0x533/0x1170 mm/filemap.c:2828
       read_mapping_page include/linux/pagemap.h:402 [inline]
       ntfs_map_page fs/ntfs/aops.h:89 [inline]
       ntfs_sync_mft_mirror+0x24f/0x1d00 fs/ntfs/mft.c:494
       write_mft_record_nolock+0x13d2/0x16c0 fs/ntfs/mft.c:801
       write_mft_record fs/ntfs/mft.h:109 [inline]
       __ntfs_write_inode+0x609/0xe10 fs/ntfs/inode.c:3064
       write_inode fs/fs-writeback.c:1244 [inline]
       __writeback_single_inode+0x733/0x11d0 fs/fs-writeback.c:1442
       writeback_sb_inodes+0x537/0xef0 fs/fs-writeback.c:1647
       wb_writeback+0x28d/0xcc0 fs/fs-writeback.c:1820
       wb_do_writeback fs/fs-writeback.c:1965 [inline]
       wb_workfn+0x29b/0x1250 fs/fs-writeback.c:2006
       process_one_work+0x864/0x1570 kernel/workqueue.c:2153
       worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
       kthread+0x33f/0x460 kernel/kthread.c:259
       ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

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);
  lock(&rl->lock);

 *** DEADLOCK ***

3 locks held by kworker/u4:0/7:
 #0: 000000003630507b ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
 #1: 000000008354c08c ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
 #2: 0000000010cc17e8 (&ni->mrec_lock){+.+.}, at: map_mft_record+0x3c/0xc70 fs/ntfs/mft.c:168

stack backtrace:
CPU: 1 PID: 7 Comm: kworker/u4:0 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222
 check_prev_add kernel/locking/lockdep.c:1866 [inline]
 check_prevs_add kernel/locking/lockdep.c:1979 [inline]
 validate_chain kernel/locking/lockdep.c:2420 [inline]
 __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416
 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
 down_read+0x36/0x80 kernel/locking/rwsem.c:24
 ntfs_read_block fs/ntfs/aops.c:265 [inline]
 ntfs_readpage+0x1909/0x21b0 fs/ntfs/aops.c:452
 do_read_cache_page+0x533/0x1170 mm/filemap.c:2828
 read_mapping_page include/linux/pagemap.h:402 [inline]
 ntfs_map_page fs/ntfs/aops.h:89 [inline]
 ntfs_sync_mft_mirror+0x24f/0x1d00 fs/ntfs/mft.c:494
 write_mft_record_nolock+0x13d2/0x16c0 fs/ntfs/mft.c:801
 write_mft_record fs/ntfs/mft.h:109 [inline]
 __ntfs_write_inode+0x609/0xe10 fs/ntfs/inode.c:3064
 write_inode fs/fs-writeback.c:1244 [inline]
 __writeback_single_inode+0x733/0x11d0 fs/fs-writeback.c:1442
 writeback_sb_inodes+0x537/0xef0 fs/fs-writeback.c:1647
 wb_writeback+0x28d/0xcc0 fs/fs-writeback.c:1820
 wb_do_writeback fs/fs-writeback.c:1965 [inline]
 wb_workfn+0x29b/0x1250 fs/fs-writeback.c:2006
 process_one_work+0x864/0x1570 kernel/workqueue.c:2153
 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_fr