======================================================
WARNING: possible circular locking dependency detected
6.1.0-next-20221214 #1 Not tainted
------------------------------------------------------
syz-executor.5/6710 is trying to acquire lock:
ffff8880107863f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: __jbd2_log_wait_for_space+0x238/0x460

but task is already holding lock:
ffff888010782530 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x1a0/0x640

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (sb_pagefaults){.+.+}-{0:0}:
       ext4_page_mkwrite+0x1fc/0x1a70
       do_page_mkwrite+0x1a0/0x640
       __handle_mm_fault+0x12ac/0x3640
       handle_mm_fault+0x2ce/0xae0
       do_user_addr_fault+0x53a/0x1300
       exc_page_fault+0x9c/0x1a0
       asm_exc_page_fault+0x26/0x30

-> #2 (&mm->mmap_lock){++++}-{3:3}:
       __might_fault+0x103/0x180
       iov_iter_zero+0x82f/0x15e0
       __iomap_dio_rw+0xec8/0x1bd0
       iomap_dio_rw+0x40/0xa0
       ext4_file_read_iter+0x2f4/0x4a0
       do_iter_readv_writev+0x2f0/0x3c0
       do_iter_read+0x2fb/0x750
       vfs_readv+0xe5/0x160
       do_readv+0x133/0x300
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

-> #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+0x857/0xc10
       __ext4_ioctl+0x9be/0x4560
       __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+0x2a02/0x5e70
       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+0x4a5/0x6b0
       ext4_dirty_inode+0xa5/0x130
       __mark_inode_dirty+0x1aa/0xe70
       generic_update_time+0x21b/0x2b0
       file_update_time+0x22f/0x280
       ext4_page_mkwrite+0x2ee/0x1a70
       do_page_mkwrite+0x1a0/0x640
       __handle_mm_fault+0x12ac/0x3640
       handle_mm_fault+0x2ce/0xae0
       do_user_addr_fault+0x53a/0x1300
       exc_page_fault+0x9c/0x1a0
       asm_exc_page_fault+0x26/0x30

other info that might help us debug this:

Chain exists of:
  &journal->j_checkpoint_mutex --> &mm->mmap_lock --> sb_pagefaults

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_pagefaults);
                               lock(&mm->mmap_lock);
                               lock(sb_pagefaults);
  lock(&journal->j_checkpoint_mutex);

 *** DEADLOCK ***

2 locks held by syz-executor.5/6710:
 #0: ffff888009cab458 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x33b/0x1300
 #1: ffff888010782530 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x1a0/0x640

stack backtrace:
CPU: 0 PID: 6710 Comm: syz-executor.5 Not tainted 6.1.0-next-20221214 #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+0x2a02/0x5e70
 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+0x4a5/0x6b0
 ext4_dirty_inode+0xa5/0x130
 __mark_inode_dirty+0x1aa/0xe70
 generic_update_time+0x21b/0x2b0
 file_update_time+0x22f/0x280
 ext4_page_mkwrite+0x2ee/0x1a70
 do_page_mkwrite+0x1a0/0x640
 __handle_mm_fault+0x12ac/0x3640
 handle_mm_fault+0x2ce/0xae0
 do_user_addr_fault+0x53a/0x1300
 exc_page_fault+0x9c/0x1a0
 asm_exc_page_fault+0x26/0x30
RIP: 0033:0x7f99b99b3673
Code: 5d c3 0f 1f 44 00 00 48 8b 0d 59 ed 0a 01 48 8b 05 4a ed 0a 01 4c 8d 81 00 00 00 01 48 39 c8 72 13 4c 39 c0 73 0e 48 8d 50 04 <89> 38 48 89 15 2c ed 0a 01 c3 52 48 8d 35 77 b7 0b 00 48 89 c2 48
RSP: 002b:00007ffe233a5218 EFLAGS: 00010287
RAX: 0000001b2c521000 RBX: 00007f99b978d008 RCX: 0000001b2c520000
RDX: 0000001b2c521004 RSI: ffffffff834f776b RDI: 000000008a7606c5
RBP: 0000000000000001 R08: 0000001b2d520000 R09: 0000001b2c52001c
R10: 00000000000006c5 R11: 000000008a7606c9 R12: 0000000000000d16
R13: 00007f99b9b1d000 R14: ffffffff834f776b R15: 00007f99b9b28ff0
 </TASK>