======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc7-next-20230213 #1 Not tainted
------------------------------------------------------
syz-executor.4/1261 is trying to acquire lock:
ffff88800ff5c3f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: __jbd2_log_wait_for_space+0x238/0x4b0

but task is already holding lock:
ffff8880422c0df0 (&sb->s_type->i_mutex_key#6){++++}-{3:3}, at: vfs_unlink+0xd9/0x930

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&sb->s_type->i_mutex_key#6){++++}-{3:3}:
       down_read+0x3d/0x50
       ext4_bmap+0x52/0x470
       bmap+0xb0/0x130
       jbd2_journal_bmap+0xac/0x1d0
       jbd2_journal_flush+0x87f/0xc90
       __ext4_ioctl+0x9fd/0x4330
       __x64_sys_ioctl+0x19e/0x210
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

-> #0 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
       __lock_acquire+0x2da7/0x63b0
       lock_acquire.part.0+0xec/0x320
       mutex_lock_io_nested+0x149/0x1300
       __jbd2_log_wait_for_space+0x238/0x4b0
       add_transaction_credits+0xa42/0xb80
       start_this_handle+0x3a6/0x14d0
       jbd2__journal_start+0x394/0x6b0
       __ext4_journal_start_sb+0x4c2/0x6f0
       __ext4_unlink+0x44e/0xcf0
       ext4_unlink+0x3ac/0x640
       vfs_unlink+0x35e/0x930
       do_unlinkat+0x3b9/0x650
       __x64_sys_unlink+0xca/0x110
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

other info that might help us debug this:

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

3 locks held by syz-executor.4/1261:
 #0: ffff88800ff58438 (sb_writers#3){.+.+}-{0:0}, at: do_unlinkat+0x190/0x650
 #1: ffff888042154990 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: do_unlinkat+0x280/0x650
 #2: ffff8880422c0df0 (&sb->s_type->i_mutex_key#6){++++}-{3:3}, at: vfs_unlink+0xd9/0x930

stack backtrace:
CPU: 0 PID: 1261 Comm: syz-executor.4 Not tainted 6.2.0-rc7-next-20230213 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x91/0xf0
 check_noncircular+0x263/0x2e0
 __lock_acquire+0x2da7/0x63b0
 lock_acquire.part.0+0xec/0x320
 mutex_lock_io_nested+0x149/0x1300
 __jbd2_log_wait_for_space+0x238/0x4b0
 add_transaction_credits+0xa42/0xb80
 start_this_handle+0x3a6/0x14d0
 jbd2__journal_start+0x394/0x6b0
 __ext4_journal_start_sb+0x4c2/0x6f0
 __ext4_unlink+0x44e/0xcf0
 ext4_unlink+0x3ac/0x640
 vfs_unlink+0x35e/0x930
 do_unlinkat+0x3b9/0x650
 __x64_sys_unlink+0xca/0x110
 do_syscall_64+0x3f/0x90
 entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7f13e9a22457
Code: 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 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:00007ffd47327908 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f13e9a22457
RDX: 00007ffd47327940 RSI: 00007ffd47327940 RDI: 00007ffd473279d0
RBP: 00007ffd473279d0 R08: 0000000000000001 R09: 00007ffd473277a0
R10: 00005555574fecdb R11: 0000000000000206 R12: 00007f13e9a7c105
R13: 00007ffd47328a90 R14: 00005555574fec20 R15: 00007ffd47328ad0
 </TASK>
IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready
device lo entered promiscuous mode
IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready
Process accounting resumed
Process accounting resumed
Process accounting resumed
Process accounting resumed
Process accounting resumed
Process accounting resumed
Process accounting resumed
Process accounting resumed
Process accounting resumed
Process accounting resumed
Process accounting resumed
Process accounting resumed
netlink: 28 bytes leftover after parsing attributes in process `syz-executor.4'.
Process accounting resumed
netlink: 28 bytes leftover after parsing attributes in process `syz-executor.4'.
netlink: 28 bytes leftover after parsing attributes in process `syz-executor.4'.
netlink: 28 bytes leftover after parsing attributes in process `syz-executor.4'.