syzbot

======================================================
WARNING: possible circular locking dependency detected
6.1.87-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor383/3543 is trying to acquire lock:
ffff888148d38400 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:768 [inline]
ffff888148d38400 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_bmap+0x4b/0x410 fs/ext4/inode.c:3176

but task is already holding lock:
ffff88807eb4e3f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x323/0xc40 fs/jbd2/journal.c:2478

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       mutex_lock_io_nested+0x134/0xab0 kernel/locking/mutex.c:833
       jbd2_journal_flush+0x29b/0xc40 fs/jbd2/journal.c:2468
       ext4_ioctl_checkpoint fs/ext4/ioctl.c:1086 [inline]
       __ext4_ioctl fs/ext4/ioctl.c:1594 [inline]
       ext4_ioctl+0x3986/0x5f60 fs/ext4/ioctl.c:1614
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #2 (&journal->j_barrier){+.+.}-{3:3}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
       jbd2_journal_lock_updates+0x2b0/0x380 fs/jbd2/transaction.c:904
       ext4_change_inode_journal_flag+0x1a8/0x6e0 fs/ext4/inode.c:6120
       ext4_ioctl_setflags fs/ext4/ioctl.c:688 [inline]
       ext4_fileattr_set+0xe04/0x1770 fs/ext4/ioctl.c:1008
       vfs_fileattr_set+0x8f3/0xd30 fs/ioctl.c:696
       ioctl_setflags fs/ioctl.c:728 [inline]
       do_vfs_ioctl+0x1cd1/0x2a90 fs/ioctl.c:839
       __do_sys_ioctl fs/ioctl.c:868 [inline]
       __se_sys_ioctl+0x81/0x160 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (&sbi->s_writepages_rwsem){++++}-{0:0}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       percpu_down_write+0x50/0x2f0 kernel/locking/percpu-rwsem.c:227
       ext4_ind_migrate+0x254/0x760 fs/ext4/migrate.c:624
       ext4_ioctl_setflags fs/ext4/ioctl.c:697 [inline]
       ext4_fileattr_set+0xe9b/0x1770 fs/ext4/ioctl.c:1008
       vfs_fileattr_set+0x8f3/0xd30 fs/ioctl.c:696
       ioctl_setflags fs/ioctl.c:728 [inline]
       do_vfs_ioctl+0x1cd1/0x2a90 fs/ioctl.c:839
       __do_sys_ioctl fs/ioctl.c:868 [inline]
       __se_sys_ioctl+0x81/0x160 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&sb->s_type->i_mutex_key#8){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       down_read+0xad/0xa30 kernel/locking/rwsem.c:1520
       inode_lock_shared include/linux/fs.h:768 [inline]
       ext4_bmap+0x4b/0x410 fs/ext4/inode.c:3176
       bmap+0xa1/0xd0 fs/inode.c:1842
       jbd2_journal_bmap fs/jbd2/journal.c:977 [inline]
       __jbd2_journal_erase fs/jbd2/journal.c:1794 [inline]
       jbd2_journal_flush+0x5b5/0xc40 fs/jbd2/journal.c:2496
       ext4_ioctl_checkpoint fs/ext4/ioctl.c:1086 [inline]
       __ext4_ioctl fs/ext4/ioctl.c:1594 [inline]
       ext4_ioctl+0x3986/0x5f60 fs/ext4/ioctl.c:1614
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

Chain exists of:
  &sb->s_type->i_mutex_key#8 --> &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#8);

 *** DEADLOCK ***

2 locks held by syz-executor383/3543:
 #0: ffff88807eb4e170 (&journal->j_barrier){+.+.}-{3:3}, at: jbd2_journal_lock_updates+0x2b0/0x380 fs/jbd2/transaction.c:904
 #1: ffff88807eb4e3f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x323/0xc40 fs/jbd2/journal.c:2478

stack backtrace:
CPU: 1 PID: 3543 Comm: syz-executor383 Not tainted 6.1.87-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 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+0x1661/0x5950 kernel/locking/lockdep.c:3825
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 down_read+0xad/0xa30 kernel/locking/rwsem.c:1520
 inode_lock_shared include/linux/fs.h:768 [inline]
 ext4_bmap+0x4b/0x410 fs/ext4/inode.c:3176
 bmap+0xa1/0xd0 fs/inode.c:1842
 jbd2_journal_bmap fs/jbd2/journal.c:977 [inline]
 __jbd2_journal_erase fs/jbd2/journal.c:1794 [inline]
 jbd2_journal_flush+0x5b5/0xc40 fs/jbd2/journal.c:2496
 ext4_ioctl_checkpoint fs/ext4/ioctl.c:1086 [inline]
 __ext4_ioctl fs/ext4/ioctl.c:1594 [inline]
 ext4_ioctl+0x3986/0x5f60 fs/ext4/ioctl.c:1614
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fbc26770369
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffbecd0b78 EFLAGS: 00000246 ORIG