======================================================
WARNING: possible circular locking dependency detected
6.1.0-rc1-next-20221018 #1 Not tainted
------------------------------------------------------
syz-executor.5/11944 is trying to acquire lock:
ffff88801002c3f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: __jbd2_log_wait_for_space+0x234/0x460

but task is already holding lock:
ffff888010028530 (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+0x1f8/0x1a70
       do_page_mkwrite+0x1a0/0x640
       __handle_mm_fault+0x12ac/0x35e0
       handle_mm_fault+0x2e6/0xa20
       do_user_addr_fault+0x536/0x1300
       exc_page_fault+0x98/0x1a0
       asm_exc_page_fault+0x22/0x30

-> #2 (&mm->mmap_lock#2){++++}-{3:3}:
       down_read+0x98/0x450
       do_user_addr_fault+0xb00/0x1300
       exc_page_fault+0x98/0x1a0
       asm_exc_page_fault+0x22/0x30
       fault_in_readable+0x143/0x250
       fault_in_iov_iter_readable+0x252/0x2c0
       generic_perform_write+0x1b0/0x580
       ext4_buffered_write_iter+0x164/0x460
       ext4_file_write_iter+0x3fb/0x1900
       vfs_write+0x9c3/0xd90
       ksys_write+0x127/0x250
       do_syscall_64+0x3b/0x90
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&sb->s_type->i_mutex_key#6){++++}-{3:3}:
       down_read+0x98/0x450
       ext4_bmap+0x4e/0x470
       bmap+0xac/0x120
       jbd2_journal_bmap+0xa8/0x180
       jbd2_journal_flush+0x853/0xc00
       __ext4_ioctl+0x9e9/0x40a0
       __x64_sys_ioctl+0x19a/0x210
       do_syscall_64+0x3b/0x90
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
       __lock_acquire+0x2a02/0x5e70
       lock_acquire+0x1a2/0x530
       mutex_lock_io_nested+0x148/0x1310
       __jbd2_log_wait_for_space+0x234/0x460
       add_transaction_credits+0xa42/0xb80
       start_this_handle+0x3ac/0x14c0
       jbd2__journal_start+0x390/0x8d0
       __ext4_journal_start_sb+0x391/0x470
       ext4_dirty_inode+0x9d/0x110
       __mark_inode_dirty+0x1a6/0xe60
       generic_update_time+0x217/0x2b0
       file_update_time+0x22b/0x280
       ext4_page_mkwrite+0x2ea/0x1a70
       do_page_mkwrite+0x1a0/0x640
       __handle_mm_fault+0x12ac/0x35e0
       handle_mm_fault+0x2e6/0xa20
       do_user_addr_fault+0x536/0x1300
       exc_page_fault+0x98/0x1a0
       asm_exc_page_fault+0x22/0x30

other info that might help us debug this:

Chain exists of:
  &journal->j_checkpoint_mutex --> &mm->mmap_lock#2 --> sb_pagefaults

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_pagefaults);
                               lock(&mm->mmap_lock#2);
                               lock(sb_pagefaults);
  lock(&journal->j_checkpoint_mutex);

 *** DEADLOCK ***

2 locks held by syz-executor.5/11944:
 #0: ffff88801df2f858 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x337/0x1300
 #1: ffff888010028530 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x1a0/0x640

stack backtrace:
CPU: 0 PID: 11944 Comm: syz-executor.5 Not tainted 6.1.0-rc1-next-20221018 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x8b/0xb3
 check_noncircular+0x263/0x2e0
 __lock_acquire+0x2a02/0x5e70
 lock_acquire+0x1a2/0x530
 mutex_lock_io_nested+0x148/0x1310
 __jbd2_log_wait_for_space+0x234/0x460
 add_transaction_credits+0xa42/0xb80
 start_this_handle+0x3ac/0x14c0
 jbd2__journal_start+0x390/0x8d0
 __ext4_journal_start_sb+0x391/0x470
 ext4_dirty_inode+0x9d/0x110
 __mark_inode_dirty+0x1a6/0xe60
 generic_update_time+0x217/0x2b0
 file_update_time+0x22b/0x280
 ext4_page_mkwrite+0x2ea/0x1a70
 do_page_mkwrite+0x1a0/0x640
 __handle_mm_fault+0x12ac/0x35e0
 handle_mm_fault+0x2e6/0xa20
 do_user_addr_fault+0x536/0x1300
 exc_page_fault+0x98/0x1a0
 asm_exc_page_fault+0x22/0x30
RIP: 0033:0x7f76b093e673
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:00007ffe943d5f28 EFLAGS: 00010287
RAX: 0000001b2eb28000 RBX: 00007f76b0718008 RCX: 0000001b2eb20000
RDX: 0000001b2eb28004 RSI: ffffffff81bc633b RDI: 0000000062a3b991
RBP: 0000000000000001 R08: 0000001b2fb20000 R09: 0000001b2eb27324
R10: 0000000000001994 R11: 0000000062a3b995 R12: 00000000000020a1
R13: 00007f76b0aa8000 R14: ffffffff81bc633b R15: 00007f76b0ab3ff0
 </TASK>
syz-executor.7 calls setitimer() with new_value NULL pointer. Misfeature support will be removed
Process accounting resumed
SELinux:  Context  is not valid (left unmapped).
Bluetooth: MGMT ver 1.22
Zero length message leads to an empty skb
mac80211_hwsim: wmediumd released netlink socket, switching to perfect channel medium
mac80211_hwsim: wmediumd released netlink socket, switching to perfect channel medium
netlink: 320 bytes leftover after parsing attributes in process `syz-executor.7'.
tmpfs: Bad value for 'mpol'
tmpfs: Bad value for 'mpol'