syzbot

warning: checkpointing journal with EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT can be slow
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc2-syzkaller-00010-g69b41ac87e4a #0 Not tainted
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syz-executor504/5066 is trying to acquire lock:
ffff888140d10400 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:766 [inline]
ffff888140d10400 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_bmap+0x55/0x410 fs/ext4/inode.c:3243

but task is already holding lock:
ffff88814c1483f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x330/0xca0 fs/jbd2/journal.c:2474

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+0x182/0x3c0 kernel/locking/lockdep.c:5668
       __mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
       mutex_lock_io_nested+0x43/0x60 kernel/locking/mutex.c:833
       jbd2_journal_flush+0x2a6/0xca0 fs/jbd2/journal.c:2464
       ext4_ioctl_checkpoint fs/ext4/ioctl.c:1082 [inline]
       __ext4_ioctl fs/ext4/ioctl.c:1590 [inline]
       ext4_ioctl+0x3224/0x54f0 fs/ext4/ioctl.c:1610
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #2 (&journal->j_barrier){+.+.}-{3:3}:
       lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
       __mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
       jbd2_journal_lock_updates+0x29d/0x370 fs/jbd2/transaction.c:904
       ext4_change_inode_journal_flag+0x1a2/0x6c0 fs/ext4/inode.c:6158
       ext4_ioctl_setflags fs/ext4/ioctl.c:687 [inline]
       ext4_fileattr_set+0xdf1/0x1810 fs/ext4/ioctl.c:1004
       vfs_fileattr_set+0x8be/0xd20 fs/ioctl.c:696
       ioctl_setflags fs/ioctl.c:728 [inline]
       do_vfs_ioctl+0x1d02/0x2980 fs/ioctl.c:839
       __do_sys_ioctl fs/ioctl.c:868 [inline]
       __se_sys_ioctl+0x83/0x170 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&sbi->s_writepages_rwsem){++++}-{0:0}:
       lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
       percpu_down_write+0x50/0x300 kernel/locking/percpu-rwsem.c:227
       ext4_ind_migrate+0x262/0x730 fs/ext4/migrate.c:624
       ext4_ioctl_setflags fs/ext4/ioctl.c:696 [inline]
       ext4_fileattr_set+0xe7c/0x1810 fs/ext4/ioctl.c:1004
       vfs_fileattr_set+0x8be/0xd20 fs/ioctl.c:696
       ioctl_setflags fs/ioctl.c:728 [inline]
       do_vfs_ioctl+0x1d02/0x2980 fs/ioctl.c:839
       __do_sys_ioctl fs/ioctl.c:868 [inline]
       __se_sys_ioctl+0x83/0x170 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&sb->s_type->i_mutex_key#8){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3097 [inline]
       check_prevs_add kernel/locking/lockdep.c:3216 [inline]
       validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
       __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
       lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
       down_read+0x39/0x50 kernel/locking/rwsem.c:1509
       inode_lock_shared include/linux/fs.h:766 [inline]
       ext4_bmap+0x55/0x410 fs/ext4/inode.c:3243
       bmap+0xa1/0xd0 fs/inode.c:1798
       jbd2_journal_bmap fs/jbd2/journal.c:977 [inline]
       __jbd2_journal_erase fs/jbd2/journal.c:1789 [inline]
       jbd2_journal_flush+0x5d0/0xca0 fs/jbd2/journal.c:2492
       ext4_ioctl_checkpoint fs/ext4/ioctl.c:1082 [inline]
       __ext4_ioctl fs/ext4/ioctl.c:1590 [inline]
       ext4_ioctl+0x3224/0x54f0 fs/ext4/ioctl.c:1610
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

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-executor504/5066:
 #0: ffff88814c148170 (&journal->j_barrier){+.+.}-{3:3}, at: jbd2_journal_lock_updates+0x29d/0x370 fs/jbd2/transaction.c:904
 #1: ffff88814c1483f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x330/0xca0 fs/jbd2/journal.c:2474

stack backtrace:
CPU: 1 PID: 5066 Comm: syz-executor504 Not tainted 6.2.0-rc2-syzkaller-00010-g69b41ac87e4a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106
 check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2177
 check_prev_add kernel/locking/lockdep.c:3097 [inline]
 check_prevs_add kernel/locking/lockdep.c:3216 [inline]
 validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
 __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
 lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
 down_read+0x39/0x50 kernel/locking/rwsem.c:1509
 inode_lock_shared include/linux/fs.h:766 [inline]
 ext4_bmap+0x55/0x410 fs/ext4/inode.c:3243
 bmap+0xa1/0xd0 fs/inode.c:1798
 jbd2_journal_bmap fs/jbd2/journal.c:977 [inline]
 __jbd2_journal_erase fs/jbd2/journal.c:1789 [inline]
 jbd2_journal_flush+0x5d0/0xca0 fs/jbd2/journal.c:2492
 ext4_ioctl_checkpoint fs/ext4/ioctl.c:1082 [inline]
 __ext4_ioctl fs/ext4/ioctl.c:1590 [inline]
 ext4_ioctl+0x3224/0x54f0 fs/ext4/ioctl.c:1610
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7ff52217bb79
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffca38b40d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff52217bb79
RDX: 0000000020000000 RSI: 000000004004662b RDI: 0000000000000004
RBP: 00007ff52213fd20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000