====================================================== WARNING: possible circular locking dependency detected 6.2.0-rc1-syzkaller-00084-gc8451c141e07 #0 Not tainted ------------------------------------------------------ syz-executor999/5404 is trying to acquire lock: ffff88814bfd43f8 (&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: ffff8880748eac20 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline] ffff8880748eac20 (&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:766 [inline] ext4_bmap+0x52/0x470 fs/ext4/inode.c:3243 bmap+0xae/0x120 fs/inode.c:1798 jbd2_journal_bmap+0xac/0x180 fs/jbd2/journal.c:977 __jbd2_journal_erase fs/jbd2/journal.c:1789 [inline] jbd2_journal_flush+0x853/0xc00 fs/jbd2/journal.c:2492 ext4_ioctl_checkpoint fs/ext4/ioctl.c:1082 [inline] __ext4_ioctl+0xb01/0x4b60 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:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 __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+0x39d/0x9b0 fs/jbd2/transaction.c:520 __ext4_journal_start_sb+0x6e9/0x860 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:6107 __mark_inode_dirty+0x247/0x11e0 fs/fs-writeback.c:2419 generic_update_time+0x21b/0x2b0 fs/inode.c:1859 inode_update_time fs/inode.c:1872 [inline] __file_update_time fs/inode.c:2057 [inline] file_modified_flags+0x2ce/0x320 fs/inode.c:2130 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 dump_emit_page fs/coredump.c:864 [inline] dump_user_range+0x234/0x700 fs/coredump.c:915 elf_core_dump+0x2718/0x3590 fs/binfmt_elf.c:2137 do_coredump+0x2764/0x3c50 fs/coredump.c:762 get_signal+0x1c03/0x2450 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+0x15f/0x250 kernel/entry/common.c:203 irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:309 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-executor999/5404: #0: ffff88814bfd0460 (sb_writers#4){.+.+}-{0:0}, at: get_signal+0x1c03/0x2450 kernel/signal.c:2845 #1: ffff8880748eac20 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline] #1: ffff8880748eac20 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_buffered_write_iter+0xb0/0x460 fs/ext4/file.c:279 stack backtrace: CPU: 1 PID: 5404 Comm: syz-executor999 Not tainted 6.2.0-rc1-syzkaller-00084-gc8451c141e07 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 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:2177 check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 __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+0x39d/0x9b0 fs/jbd2/transaction.c:520 __ext4_journal_start_sb+0x6e9/0x860 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:6107 __mark_inode_dirty+0x247/0x11e0 fs/fs-writeback.c:2419 generic_update_time+0x21b/0x2b0 fs/inode.c:1859 inode_update_time fs/inode.c:1872 [inline] __file_update_time fs/inode.c:2057 [inline] file_modified_flags+0x2ce/0x320 fs/inode.c:2130 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 dump_emit_page fs/coredump.c:864 [inline] dump_user_range+0x234/0x700 fs/coredump.c:915 elf_core_dump+0x2718/0x3590 fs/binfmt_elf.c:2137 do_coredump+0x2764/0x3c50 fs/coredump.c:762 get_signal+0x1c03/0x2450 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+0x15f/0x250 kernel/entry/common.c:203 irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:309 asm_exc_general_protection+0x26/0x30 arch/x86/include/asm/idtentry.h:564 RIP: 0033:0x7fd2230859c1 Code: c4 28 c3 e8 71 15 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: 0000000000000000 RCX: 00007fd2230859b9 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000020002000 RBP: 00007fd22310a400 R08: 0000000000000000 R09: 00007fd22310a408 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd22310a40c R13: 00007ffc73475fbf R14: 00007fd222ff0300 R15: 0000000000022000