====================================================== WARNING: possible circular locking dependency detected 6.2.0-rc5-next-20230123-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.4/7828 is trying to acquire lock: ffff88802bb9a3f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: __jbd2_log_wait_for_space+0x238/0x460 fs/jbd2/checkpoint.c:110 but task is already holding lock: ffff8880723db628 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] ffff8880723db628 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_buffered_write_iter+0xb0/0x460 fs/ext4/file.c:279 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sb->s_type->i_mutex_key#8){++++}-{3:3}: down_read+0x9c/0x450 kernel/locking/rwsem.c:1509 inode_lock_shared include/linux/fs.h:768 [inline] ext4_bmap+0x52/0x470 fs/ext4/inode.c:3242 bmap+0xae/0x120 fs/inode.c:1799 jbd2_journal_bmap+0xac/0x180 fs/jbd2/journal.c:976 __jbd2_journal_erase fs/jbd2/journal.c:1788 [inline] jbd2_journal_flush+0x85c/0xc10 fs/jbd2/journal.c:2491 ext4_ioctl_checkpoint fs/ext4/ioctl.c:1082 [inline] __ext4_ioctl+0xb3f/0x4c00 fs/ext4/ioctl.c:1590 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #0 (&journal->j_checkpoint_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3107 [inline] check_prevs_add kernel/locking/lockdep.c:3226 [inline] validate_chain kernel/locking/lockdep.c:3841 [inline] __lock_acquire+0x2a9d/0x5780 kernel/locking/lockdep.c:5073 lock_acquire.part.0+0x11c/0x350 kernel/locking/lockdep.c:5690 __mutex_lock_common kernel/locking/mutex.c:603 [inline] mutex_lock_io_nested+0x143/0x11a0 kernel/locking/mutex.c:833 __jbd2_log_wait_for_space+0x238/0x460 fs/jbd2/checkpoint.c:110 add_transaction_credits+0xa2d/0xb70 fs/jbd2/transaction.c:298 start_this_handle+0x3ae/0x14a0 fs/jbd2/transaction.c:422 jbd2__journal_start+0x38a/0x6b0 fs/jbd2/transaction.c:520 __ext4_journal_start_sb+0x706/0x890 fs/ext4/ext4_jbd2.c:111 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_dirty_inode+0xa5/0x130 fs/ext4/inode.c:6106 __mark_inode_dirty+0x247/0x1250 fs/fs-writeback.c:2421 generic_update_time+0x21b/0x2b0 fs/inode.c:1860 inode_update_time fs/inode.c:1873 [inline] __file_update_time fs/inode.c:2058 [inline] file_modified_flags+0x2ce/0x320 fs/inode.c:2131 ext4_write_checks fs/ext4/file.c:264 [inline] ext4_buffered_write_iter+0xf9/0x460 fs/ext4/file.c:280 ext4_file_write_iter+0x8bf/0x1710 fs/ext4/file.c:700 __kernel_write_iter+0x262/0x730 fs/read_write.c:517 __kernel_write+0xcb/0x110 fs/read_write.c:537 __dump_emit fs/coredump.c:811 [inline] dump_emit+0x21d/0x340 fs/coredump.c:848 writenote+0x20f/0x2b0 fs/binfmt_elf.c:1487 write_note_info fs/binfmt_elf.c:1972 [inline] elf_core_dump+0x24d5/0x3690 fs/binfmt_elf.c:2129 do_coredump+0x2769/0x3c40 fs/coredump.c:762 get_signal+0x1c08/0x24f0 kernel/signal.c:2845 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204 irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:310 asm_exc_general_protection+0x26/0x30 arch/x86/include/asm/idtentry.h:564 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#8); lock(&journal->j_checkpoint_mutex); lock(&sb->s_type->i_mutex_key#8); lock(&journal->j_checkpoint_mutex); *** DEADLOCK *** 2 locks held by syz-executor.4/7828: #0: ffff88802bb96460 (sb_writers#4){.+.+}-{0:0}, at: get_signal+0x1c08/0x24f0 kernel/signal.c:2845 #1: ffff8880723db628 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff8880723db628 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_buffered_write_iter+0xb0/0x460 fs/ext4/file.c:279 stack backtrace: CPU: 0 PID: 7828 Comm: syz-executor.4 Not tainted 6.2.0-rc5-next-20230123-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3107 [inline] check_prevs_add kernel/locking/lockdep.c:3226 [inline] validate_chain kernel/locking/lockdep.c:3841 [inline] __lock_acquire+0x2a9d/0x5780 kernel/locking/lockdep.c:5073 lock_acquire.part.0+0x11c/0x350 kernel/locking/lockdep.c:5690 __mutex_lock_common kernel/locking/mutex.c:603 [inline] mutex_lock_io_nested+0x143/0x11a0 kernel/locking/mutex.c:833 __jbd2_log_wait_for_space+0x238/0x460 fs/jbd2/checkpoint.c:110 add_transaction_credits+0xa2d/0xb70 fs/jbd2/transaction.c:298 start_this_handle+0x3ae/0x14a0 fs/jbd2/transaction.c:422 jbd2__journal_start+0x38a/0x6b0 fs/jbd2/transaction.c:520 __ext4_journal_start_sb+0x706/0x890 fs/ext4/ext4_jbd2.c:111 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_dirty_inode+0xa5/0x130 fs/ext4/inode.c:6106 __mark_inode_dirty+0x247/0x1250 fs/fs-writeback.c:2421 generic_update_time+0x21b/0x2b0 fs/inode.c:1860 inode_update_time fs/inode.c:1873 [inline] __file_update_time fs/inode.c:2058 [inline] file_modified_flags+0x2ce/0x320 fs/inode.c:2131 ext4_write_checks fs/ext4/file.c:264 [inline] ext4_buffered_write_iter+0xf9/0x460 fs/ext4/file.c:280 ext4_file_write_iter+0x8bf/0x1710 fs/ext4/file.c:700 __kernel_write_iter+0x262/0x730 fs/read_write.c:517 __kernel_write+0xcb/0x110 fs/read_write.c:537 __dump_emit fs/coredump.c:811 [inline] dump_emit+0x21d/0x340 fs/coredump.c:848 writenote+0x20f/0x2b0 fs/binfmt_elf.c:1487 write_note_info fs/binfmt_elf.c:1972 [inline] elf_core_dump+0x24d5/0x3690 fs/binfmt_elf.c:2129 do_coredump+0x2769/0x3c40 fs/coredump.c:762 get_signal+0x1c08/0x24f0 kernel/signal.c:2845 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204 irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:310 asm_exc_general_protection+0x26/0x30 arch/x86/include/asm/idtentry.h:564 RIP: 0033:0x7f506548c0d1 Code: c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 48 3d 01 f0 ff ff 73 01 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f RSP: 002b:0000000020000000 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f50655ac1f0 RCX: 00007f506548c0c9 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000020002000 RBP: 00007f50654e7ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007fffc9e576cf R14: 00007f50661df300 R15: 0000000000022000