======================================================
WARNING: possible circular locking dependency detected
6.2.0-next-20230303 #1 Not tainted
------------------------------------------------------
kworker/u4:0/9 is trying to acquire lock:
ffff88800ff723f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: __jbd2_log_wait_for_space+0x238/0x4b0

but task is already holding lock:
ffff88800ff70b90 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x1ad/0x650

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&sbi->s_writepages_rwsem){++++}-{0:0}:
       ext4_writepages+0x1a9/0x5e0
       do_writepages+0x1ad/0x650
       filemap_fdatawrite_wbc+0x14b/0x1b0
       __filemap_fdatawrite_range+0xba/0x100
       filemap_write_and_wait_range+0xa5/0x130
       __iomap_dio_rw+0x5ea/0x1ce0
       iomap_dio_rw+0x40/0xa0
       ext4_file_read_iter+0x2f4/0x4a0
       generic_file_splice_read+0x18b/0x4d0
       do_splice_to+0x1bc/0x240
       splice_direct_to_actor+0x2b0/0x8c0
       do_splice_direct+0x1bc/0x290
       do_sendfile+0xb1d/0x12b0
       __x64_sys_sendfile64+0x1d5/0x210
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

-> #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+0x2d56/0x6380
       lock_acquire.part.0+0xea/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_do_writepages+0xbb5/0x33f0
       ext4_writepages+0x274/0x5e0
       do_writepages+0x1ad/0x650
       __writeback_single_inode+0x105/0xfe0
       writeback_sb_inodes+0x546/0xed0
       __writeback_inodes_wb+0xbe/0x270
       wb_writeback+0x749/0xbb0
       wb_workfn+0x7be/0x1110
       process_one_work+0xa0f/0x1790
       worker_thread+0x63b/0x1260
       kthread+0x2e9/0x3a0
       ret_from_fork+0x2c/0x50

other info that might help us debug this:

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

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

4 locks held by kworker/u4:0/9:
 #0: ffff888008f58138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x90d/0x1790
 #1: ffff888008d47db0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x941/0x1790
 #2: ffff88800ff660e0 (&type->s_umount_key#42){++++}-{3:3}, at: trylock_super+0x21/0x110
 #3: ffff88800ff70b90 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x1ad/0x650

stack backtrace:
CPU: 0 PID: 9 Comm: kworker/u4:0 Not tainted 6.2.0-next-20230303 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
 <TASK>
 dump_stack_lvl+0x91/0xf0
 check_noncircular+0x263/0x2e0
 __lock_acquire+0x2d56/0x6380
 lock_acquire.part.0+0xea/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_do_writepages+0xbb5/0x33f0
 ext4_writepages+0x274/0x5e0
 do_writepages+0x1ad/0x650
 __writeback_single_inode+0x105/0xfe0
 writeback_sb_inodes+0x546/0xed0
 __writeback_inodes_wb+0xbe/0x270
 wb_writeback+0x749/0xbb0
 wb_workfn+0x7be/0x1110
 process_one_work+0xa0f/0x1790
 worker_thread+0x63b/0x1260
 kthread+0x2e9/0x3a0
 ret_from_fork+0x2c/0x50
 </TASK>
Bluetooth: hci0: ACL packet for unknown connection handle 200
Bluetooth: hci0: ACL packet for unknown connection handle 200