======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc4-next-20230119 #1 Not tainted
------------------------------------------------------
syz-executor.6/16853 is trying to acquire lock:
ffff88800c160400 (&sb->s_type->i_mutex_key#6){++++}-{3:3}, at: ext4_bmap+0x52/0x470

but task is already holding lock:
ffff88800ff8e3f8 (&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:

-> #1 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
       mutex_lock_io_nested+0x14c/0x1300
       __jbd2_log_wait_for_space+0x238/0x460
       add_transaction_credits+0xa42/0xb80
       start_this_handle+0x3ac/0x14c0
       jbd2__journal_start+0x394/0x6b0
       __ext4_journal_start_sb+0x4c2/0x6f0
       ext4_dirty_inode+0xa5/0x130
       __mark_inode_dirty+0x1aa/0xee0
       generic_write_end+0x319/0x3d0
       ext4_da_write_end+0x162/0x950
       generic_perform_write+0x318/0x580
       ext4_buffered_write_iter+0x164/0x460
       ext4_file_write_iter+0x3ff/0x1930
       vfs_write+0x9c7/0xdd0
       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+0x2a52/0x5e90
       lock_acquire.part.0+0x120/0x340
       down_read+0x9c/0x450
       ext4_bmap+0x52/0x470
       bmap+0xb0/0x130
       jbd2_journal_bmap+0xac/0x190
       jbd2_journal_flush+0x860/0xc10
       __ext4_ioctl+0x9e3/0x43e0
       __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:

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

2 locks held by syz-executor.6/16853:
 #0: ffff88800ff8e170 (&journal->j_barrier){+.+.}-{3:3}, at: jbd2_journal_lock_updates+0x162/0x310
 #1: ffff88800ff8e3f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x48f/0xc10

stack backtrace:
CPU: 1 PID: 16853 Comm: syz-executor.6 Not tainted 6.2.0-rc4-next-20230119 #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+0x2a52/0x5e90
 lock_acquire.part.0+0x120/0x340
 down_read+0x9c/0x450
 ext4_bmap+0x52/0x470
 bmap+0xb0/0x130
 jbd2_journal_bmap+0xac/0x190
 jbd2_journal_flush+0x860/0xc10
 __ext4_ioctl+0x9e3/0x43e0
 __x64_sys_ioctl+0x19e/0x210
 do_syscall_64+0x3f/0x90
 entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7faa59bfcb19
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:00007faa57172188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007faa59d0ff60 RCX: 00007faa59bfcb19
RDX: 0000000020000340 RSI: 000000004004662b RDI: 0000000000000005
RBP: 00007faa59c56f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffdeb9b62f R14: 00007faa57172300 R15: 0000000000022000
 </TASK>
device lo entered promiscuous mode
syz_tun: mtu greater than device maximum
syz_tun: mtu greater than device maximum
device lo left promiscuous mode
device lo entered promiscuous mode
device lo left promiscuous mode
device lo entered promiscuous mode
device lo left promiscuous mode
device lo entered promiscuous mode
device lo left promiscuous mode
device lo left promiscuous mode
device lo entered promiscuous mode
device lo entered promiscuous mode
device lo left promiscuous mode
device lo entered promiscuous mode
device lo left promiscuous mode
device lo entered promiscuous mode
device lo left promiscuous mode
device lo left promiscuous mode
device lo entered promiscuous mode
device lo entered promiscuous mode
ieee80211 phy66: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy67: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy68: Selected rate control algorithm 'minstrel_ht'
ieee80211 phy69: Selected rate control algorithm 'minstrel_ht'