warning: checkpointing journal with EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT can be slow ====================================================== WARNING: possible circular locking dependency detected 6.1.96-syzkaller #0 Not tainted ------------------------------------------------------ syz.1.6662/27271 is trying to acquire lock: ffff888027c58400 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:768 [inline] ffff888027c58400 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_bmap+0x4b/0x410 fs/ext4/inode.c:3176 but task is already holding lock: ffff88807e9d23f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x323/0xc40 fs/jbd2/journal.c:2478 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&journal->j_checkpoint_mutex){+.+.}-{3:3}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] mutex_lock_io_nested+0x134/0xab0 kernel/locking/mutex.c:833 __jbd2_log_wait_for_space+0x213/0x760 fs/jbd2/checkpoint.c:71 add_transaction_credits fs/jbd2/transaction.c:298 [inline] start_this_handle+0x1040/0x21b0 fs/jbd2/transaction.c:422 jbd2__journal_start+0x2d1/0x5c0 fs/jbd2/transaction.c:520 __ext4_journal_start_sb+0x19b/0x410 fs/ext4/ext4_jbd2.c:105 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] __ext4_unlink+0x412/0xba0 fs/ext4/namei.c:3265 ext4_unlink+0x1d5/0x670 fs/ext4/namei.c:3324 vfs_unlink+0x359/0x5f0 fs/namei.c:4324 do_unlinkat+0x4a5/0x820 fs/namei.c:4392 __do_sys_unlink fs/namei.c:4440 [inline] __se_sys_unlink fs/namei.c:4438 [inline] __x64_sys_unlink+0x45/0x50 fs/namei.c:4438 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&sb->s_type->i_mutex_key#8){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 down_read+0xad/0xa30 kernel/locking/rwsem.c:1520 inode_lock_shared include/linux/fs.h:768 [inline] ext4_bmap+0x4b/0x410 fs/ext4/inode.c:3176 bmap+0xa1/0xd0 fs/inode.c:1842 jbd2_journal_bmap fs/jbd2/journal.c:977 [inline] __jbd2_journal_erase fs/jbd2/journal.c:1794 [inline] jbd2_journal_flush+0x5b5/0xc40 fs/jbd2/journal.c:2496 ext4_ioctl_checkpoint fs/ext4/ioctl.c:1086 [inline] __ext4_ioctl fs/ext4/ioctl.c:1594 [inline] ext4_ioctl+0x3986/0x5f60 fs/ext4/ioctl.c:1614 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&journal->j_checkpoint_mutex); lock(&sb->s_type->i_mutex_key#8); lock(&journal->j_checkpoint_mutex); lock(&sb->s_type->i_mutex_key#8); *** DEADLOCK *** 2 locks held by syz.1.6662/27271: #0: ffff88807e9d2170 (&journal->j_barrier){+.+.}-{3:3}, at: jbd2_journal_lock_updates+0x2b0/0x380 fs/jbd2/transaction.c:904 #1: ffff88807e9d23f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x323/0xc40 fs/jbd2/journal.c:2478 stack backtrace: CPU: 1 PID: 27271 Comm: syz.1.6662 Not tainted 6.1.96-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 down_read+0xad/0xa30 kernel/locking/rwsem.c:1520 inode_lock_shared include/linux/fs.h:768 [inline] ext4_bmap+0x4b/0x410 fs/ext4/inode.c:3176 bmap+0xa1/0xd0 fs/inode.c:1842 jbd2_journal_bmap fs/jbd2/journal.c:977 [inline] __jbd2_journal_erase fs/jbd2/journal.c:1794 [inline] jbd2_journal_flush+0x5b5/0xc40 fs/jbd2/journal.c:2496 ext4_ioctl_checkpoint fs/ext4/ioctl.c:1086 [inline] __ext4_ioctl fs/ext4/ioctl.c:1594 [inline] ext4_ioctl+0x3986/0x5f60 fs/ext4/ioctl.c:1614 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f5f73575b99 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f5f7443d048 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f5f73703fa0 RCX: 00007f5f73575b99 RDX: 00000000200000c0 RSI: 000000004004662b RDI: 0000000000000003 RBP: 00007f5f735f677e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f5f73703fa0 R15: 00007ffc92bf76d8