warning: checkpointing journal with EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT can be slow
======================================================
WARNING: possible circular locking dependency detected
6.1.0-next-20221214 #1 Not tainted
------------------------------------------------------
syz-executor.4/7361 is trying to acquire lock:
ffff88800bd28400 (&sb->s_type->i_mutex_key#6){++++}-{3:3}, at: ext4_bmap+0x52/0x470

but task is already holding lock:
ffff8880108e63f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x48f/0xc10

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
       mutex_lock_io_nested+0x14c/0x1330
       jbd2_journal_flush+0x19e/0xc10
       ext4_change_inode_journal_flag+0x39d/0x550
       ext4_fileattr_set+0x14fa/0x19f0
       vfs_fileattr_set+0x780/0xb90
       do_vfs_ioctl+0xa6c/0x1af0
       __x64_sys_ioctl+0x110/0x210
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

-> #2 (&journal->j_barrier){+.+.}-{3:3}:
       __mutex_lock+0x136/0x14e0
       jbd2_journal_lock_updates+0x162/0x310
       ext4_change_inode_journal_flag+0x187/0x550
       ext4_fileattr_set+0x14fa/0x19f0
       vfs_fileattr_set+0x780/0xb90
       do_vfs_ioctl+0xa6c/0x1af0
       __x64_sys_ioctl+0x110/0x210
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

-> #1 (&sbi->s_writepages_rwsem){++++}-{0:0}:
       ext4_writepages+0x1a9/0x5b0
       do_writepages+0x1b4/0x6a0
       filemap_fdatawrite_wbc+0x14b/0x1b0
       __filemap_fdatawrite_range+0xba/0x100
       filemap_write_and_wait_range+0xa5/0x130
       __iomap_dio_rw+0x5ea/0x1bd0
       iomap_dio_rw+0x40/0xa0
       ext4_file_write_iter+0xb5d/0x1930
       vfs_write+0xa4f/0xe40
       ksys_write+0x12b/0x260
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

-> #0 (&sb->s_type->i_mutex_key#6){++++}-{3:3}:
       __lock_acquire+0x2a02/0x5e70
       lock_acquire.part.0+0x11e/0x340
       down_read+0x9c/0x450
       ext4_bmap+0x52/0x470
       bmap+0xb0/0x130
       jbd2_journal_bmap+0xac/0x190
       jbd2_journal_flush+0x857/0xc10
       __ext4_ioctl+0x9be/0x4560
       __x64_sys_ioctl+0x19e/0x210
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

other info that might help us debug this:

Chain exists of:
  &sb->s_type->i_mutex_key#6 --> &journal->j_barrier --> &journal->j_checkpoint_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&journal->j_checkpoint_mutex);
                               lock(&journal->j_barrier);
                               lock(&journal->j_checkpoint_mutex);
  lock(&sb->s_type->i_mutex_key#6);

 *** DEADLOCK ***

2 locks held by syz-executor.4/7361:
 #0: ffff8880108e6170 (&journal->j_barrier){+.+.}-{3:3}, at: jbd2_journal_lock_updates+0x162/0x310
 #1: ffff8880108e63f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x48f/0xc10

stack backtrace:
CPU: 1 PID: 7361 Comm: syz-executor.4 Not tainted 6.1.0-next-20221214 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x8f/0xb7
 check_noncircular+0x263/0x2e0
 __lock_acquire+0x2a02/0x5e70
 lock_acquire.part.0+0x11e/0x340
 down_read+0x9c/0x450
 ext4_bmap+0x52/0x470
 bmap+0xb0/0x130
 jbd2_journal_bmap+0xac/0x190
 jbd2_journal_flush+0x857/0xc10
 __ext4_ioctl+0x9be/0x4560
 __x64_sys_ioctl+0x19e/0x210
 do_syscall_64+0x3f/0x90
 entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7fcb820dbb19
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcb7f651188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fcb821eef60 RCX: 00007fcb820dbb19
RDX: 0000000020000000 RSI: 000000004004662b RDI: 0000000000000006
RBP: 00007fcb82135f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff1993984f R14: 00007fcb7f651300 R15: 0000000000022000
 </TASK>
netlink: 168 bytes leftover after parsing attributes in process `syz-executor.1'.
netlink: 168 bytes leftover after parsing attributes in process `syz-executor.1'.
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.6'.
ieee80211 phy20: Selected rate control algorithm 'minstrel_ht'
No source specified
No source specified
EXT4-fs (sda): re-mounted 7b5d9a40-9011-49ec-8035-27953f97a4d8. Quota mode: none.
EXT4-fs (sda): re-mounted 7b5d9a40-9011-49ec-8035-27953f97a4d8. Quota mode: none.
ieee80211 phy21: Selected rate control algorithm 'minstrel_ht'
EXT4-fs (sda): re-mounted 7b5d9a40-9011-49ec-8035-27953f97a4d8. Quota mode: none.
ieee80211 phy22: Selected rate control algorithm 'minstrel_ht'
EXT4-fs (sda): re-mounted 7b5d9a40-9011-49ec-8035-27953f97a4d8. Quota mode: none.
ieee80211 phy23: Selected rate control algorithm 'minstrel_ht'
EXT4-fs (sda): re-mounted 7b5d9a40-9011-49ec-8035-27953f97a4d8. Quota mode: none.
netlink: 8 bytes leftover after parsing attributes in process `syz-executor.7'.