======================================================
WARNING: possible circular locking dependency detected
5.15.152-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/4422 is trying to acquire lock:
ffff0000d45ac3f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: __jbd2_log_wait_for_space+0x1a4/0x5cc fs/jbd2/checkpoint.c:71

but task is already holding lock:
ffff0000e3727198 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
ffff0000e3727198 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: ext4_buffered_write_iter+0x9c/0x528 fs/ext4/file.c:262

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&sb->s_type->i_mutex_key#9){++++}-{3:3}:
       down_read+0xc0/0x398 kernel/locking/rwsem.c:1488
       inode_lock_shared include/linux/fs.h:799 [inline]
       ext4_bmap+0x58/0x36c fs/ext4/inode.c:3152
       bmap+0xa8/0xe8 fs/inode.c:1756
       jbd2_journal_bmap fs/jbd2/journal.c:980 [inline]
       __jbd2_journal_erase fs/jbd2/journal.c:1790 [inline]
       jbd2_journal_flush+0x63c/0xaa0 fs/jbd2/journal.c:2496
       ext4_ioctl_checkpoint fs/ext4/ioctl.c:849 [inline]
       __ext4_ioctl fs/ext4/ioctl.c:1267 [inline]
       ext4_ioctl+0x3454/0x61bc fs/ext4/ioctl.c:1276
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl fs/ioctl.c:860 [inline]
       __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
       lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
       mutex_lock_io_nested+0xcc/0x12c kernel/locking/mutex.c:777
       __jbd2_log_wait_for_space+0x1a4/0x5cc fs/jbd2/checkpoint.c:71
       add_transaction_credits+0x814/0xb90 fs/jbd2/transaction.c:299
       start_this_handle+0x578/0x12a4 fs/jbd2/transaction.c:423
       jbd2__journal_start+0x29c/0x7b4 fs/jbd2/transaction.c:521
       __ext4_journal_start_sb+0x358/0x70c fs/ext4/ext4_jbd2.c:105
       __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
       ext4_dirty_inode+0x9c/0x100 fs/ext4/inode.c:5990
       __mark_inode_dirty+0x2b0/0x10f4 fs/fs-writeback.c:2464
       generic_update_time+0x218/0x23c fs/inode.c:1817
       inode_update_time fs/inode.c:1830 [inline]
       file_update_time+0x378/0x3f0 fs/inode.c:2019
       file_modified+0x74/0xb4 fs/inode.c:2042
       ext4_write_checks fs/ext4/file.c:247 [inline]
       ext4_buffered_write_iter+0x28c/0x528 fs/ext4/file.c:263
       ext4_file_write_iter+0x688/0x162c
       __kernel_write+0x488/0x8b0 fs/read_write.c:539
       __dump_emit+0x200/0x338 fs/coredump.c:875
       dump_emit+0x288/0x36c fs/coredump.c:912
       writenote+0x114/0x330 fs/binfmt_elf.c:1463
       write_note_info fs/binfmt_elf.c:1929 [inline]
       elf_core_dump+0x2b5c/0x3640 fs/binfmt_elf.c:2272
       do_coredump+0x12c8/0x2890 fs/coredump.c:826
       get_signal+0x3dc/0x1550 kernel/signal.c:2875
       do_signal arch/arm64/kernel/signal.c:890 [inline]
       do_notify_resume+0x320/0x32b8 arch/arm64/kernel/signal.c:943
       prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline]
       exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline]
       el0_da+0x118/0x20c arch/arm64/kernel/entry-common.c:495
       el0t_64_sync_handler+0xc0/0xe4 arch/arm64/kernel/entry-common.c:629
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sb->s_type->i_mutex_key#9);
                               lock(&journal->j_checkpoint_mutex);
                               lock(&sb->s_type->i_mutex_key#9);
  lock(&journal->j_checkpoint_mutex);

 *** DEADLOCK ***

2 locks held by syz-executor.1/4422:
 #0: ffff0000d45a6460 (sb_writers#3){.+.+}-{0:0}, at: do_coredump+0x12a4/0x2890 fs/coredump.c:825
 #1: ffff0000e3727198 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
 #1: ffff0000e3727198 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: ext4_buffered_write_iter+0x9c/0x528 fs/ext4/file.c:262

stack backtrace:
CPU: 1 PID: 4422 Comm: syz-executor.1 Not tainted 5.15.152-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
 mutex_lock_io_nested+0xcc/0x12c kernel/locking/mutex.c:777
 __jbd2_log_wait_for_space+0x1a4/0x5cc fs/jbd2/checkpoint.c:71
 add_transaction_credits+0x814/0xb90 fs/jbd2/transaction.c:299
 start_this_handle+0x578/0x12a4 fs/jbd2/transaction.c:423
 jbd2__journal_start+0x29c/0x7b4 fs/jbd2/transaction.c:521
 __ext4_journal_start_sb+0x358/0x70c fs/ext4/ext4_jbd2.c:105
 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
 ext4_dirty_inode+0x9c/0x100 fs/ext4/inode.c:5990
 __mark_inode_dirty+0x2b0/0x10f4 fs/fs-writeback.c:2464
 generic_update_time+0x218/0x23c fs/inode.c:1817
 inode_update_time fs/inode.c:1830 [inline]
 file_update_time+0x378/0x3f0 fs/inode.c:2019
 file_modified+0x74/0xb4 fs/inode.c:2042
 ext4_write_checks fs/ext4/file.c:247 [inline]
 ext4_buffered_write_iter+0x28c/0x528 fs/ext4/file.c:263
 ext4_file_write_iter+0x688/0x162c
 __kernel_write+0x488/0x8b0 fs/read_write.c:539
 __dump_emit+0x200/0x338 fs/coredump.c:875
 dump_emit+0x288/0x36c fs/coredump.c:912
 writenote+0x114/0x330 fs/binfmt_elf.c:1463
 write_note_info fs/binfmt_elf.c:1929 [inline]
 elf_core_dump+0x2b5c/0x3640 fs/binfmt_elf.c:2272
 do_coredump+0x12c8/0x2890 fs/coredump.c:826
 get_signal+0x3dc/0x1550 kernel/signal.c:2875
 do_signal arch/arm64/kernel/signal.c:890 [inline]
 do_notify_resume+0x320/0x32b8 arch/arm64/kernel/signal.c:943
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline]
 el0_da+0x118/0x20c arch/arm64/kernel/entry-common.c:495
 el0t_64_sync_handler+0xc0/0xe4 arch/arm64/kernel/entry-common.c:629
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584