blktrace: Concurrent blktraces are not allowed on sg0
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc3-next-20230111 #1 Not tainted
------------------------------------------------------
rs:main Q:Reg/164 is trying to acquire lock:
ffff88800fe683f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: __jbd2_log_wait_for_space+0x238/0x460

but task is already holding lock:
ffff88801a248400 (&sb->s_type->i_mutex_key#6){++++}-{3:3}, at: ext4_buffered_write_iter+0xb0/0x460

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+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

-> #0 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
       __lock_acquire+0x2999/0x5e00
       lock_acquire.part.0+0x11e/0x340
       mutex_lock_io_nested+0x14c/0x1330
       __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_update_time+0x21b/0x2b0
       file_modified_flags+0x2d4/0x330
       ext4_buffered_write_iter+0xf9/0x460
       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

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 rs:main Q:Reg/164:
 #0: ffff88800efd4d68 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xeb/0x110
 #1: ffff88800fe54438 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x12b/0x260
 #2: ffff88801a248400 (&sb->s_type->i_mutex_key#6){++++}-{3:3}, at: ext4_buffered_write_iter+0xb0/0x460

stack backtrace:
CPU: 0 PID: 164 Comm: rs:main Q:Reg Not tainted 6.2.0-rc3-next-20230111 #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+0x2999/0x5e00
 lock_acquire.part.0+0x11e/0x340
 mutex_lock_io_nested+0x14c/0x1330
 __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_update_time+0x21b/0x2b0
 file_modified_flags+0x2d4/0x330
 ext4_buffered_write_iter+0xf9/0x460
 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
RIP: 0033:0x7f809367dfef
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 29 fd ff ff 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 5c fd ff ff 48
RSP: 002b:00007f8092839860 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f808802a940 RCX: 00007f809367dfef
RDX: 0000000000000067 RSI: 00007f808802ac00 RDI: 000000000000000b
RBP: 0000000000000067 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f808802ac00
R13: 0000000000000000 R14: 0000000000000067 R15: 00007f808802a940
 </TASK>
blktrace: Concurrent blktraces are not allowed on sg0
random: crng reseeded on system resumption
Restarting kernel threads ... done.
random: crng reseeded on system resumption
random: crng reseeded on system resumption
Restarting kernel threads ... done.
random: crng reseeded on system resumption
Restarting kernel threads ... done.
random: crng reseeded on system resumption
Restarting kernel threads ... done.
selinux_netlink_send: 1 callbacks suppressed
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=1794 sclass=netlink_route_socket pid=11908 comm=syz-executor.0
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=1794 sclass=netlink_route_socket pid=11908 comm=syz-executor.0