warning: checkpointing journal with EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT can be slow ====================================================== WARNING: possible circular locking dependency detected 6.2.0-rc2-next-20230105 #1 Not tainted ------------------------------------------------------ syz-executor.0/9648 is trying to acquire lock: ffff88800b558400 (&sb->s_type->i_mutex_key#6){++++}-{3:3}, at: ext4_bmap+0x52/0x470 but task is already holding lock: ffff88800ff283f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x48f/0xc10 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&journal->j_checkpoint_mutex){+.+.}-{3:3}: mutex_lock_io_nested+0x14c/0x1330 __jbd2_log_wait_for_space+0x238/0x460 add_transaction_credits+0xa42/0xb80 start_this_handle+0x3ac/0x14c0 jbd2__journal_start+0x394/0x6b0 __ext4_journal_start_sb+0x4c2/0x6f0 ext4_dirty_inode+0xa5/0x130 __mark_inode_dirty+0x1aa/0xee0 generic_update_time+0x21b/0x2b0 file_modified_flags+0x2d4/0x330 ext4_buffered_write_iter+0xf9/0x460 ext4_file_write_iter+0x3ff/0x1930 do_iter_readv_writev+0x211/0x3c0 do_iter_write+0x18b/0x700 vfs_writev+0x1ae/0x670 __x64_sys_pwritev+0x233/0x310 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc -> #0 (&sb->s_type->i_mutex_key#6){++++}-{3:3}: __lock_acquire+0x2a02/0x5e70 lock_acquire.part.0+0x11e/0x340 down_read+0x9c/0x450 ext4_bmap+0x52/0x470 bmap+0xb0/0x130 jbd2_journal_bmap+0xac/0x190 jbd2_journal_flush+0x857/0xc10 __ext4_ioctl+0x9db/0x43d0 __x64_sys_ioctl+0x19e/0x210 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc 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#6); lock(&journal->j_checkpoint_mutex); lock(&sb->s_type->i_mutex_key#6); *** DEADLOCK *** 2 locks held by syz-executor.0/9648: #0: ffff88800ff28170 (&journal->j_barrier){+.+.}-{3:3}, at: jbd2_journal_lock_updates+0x162/0x310 #1: ffff88800ff283f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x48f/0xc10 stack backtrace: CPU: 1 PID: 9648 Comm: syz-executor.0 Not tainted 6.2.0-rc2-next-20230105 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Call Trace: dump_stack_lvl+0x8f/0xb7 check_noncircular+0x263/0x2e0 __lock_acquire+0x2a02/0x5e70 lock_acquire.part.0+0x11e/0x340 down_read+0x9c/0x450 ext4_bmap+0x52/0x470 bmap+0xb0/0x130 jbd2_journal_bmap+0xac/0x190 jbd2_journal_flush+0x857/0xc10 __ext4_ioctl+0x9db/0x43d0 __x64_sys_ioctl+0x19e/0x210 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc RIP: 0033:0x7fda7e091b19 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fda7b607188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fda7e1a4f60 RCX: 00007fda7e091b19 RDX: 0000000020000000 RSI: 000000004004662b RDI: 0000000000000006 RBP: 00007fda7e0ebf6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff3a6fc73f R14: 00007fda7b607300 R15: 0000000000022000 netlink: 'syz-executor.5': attribute type 11 has an invalid length. netlink: 16 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 'syz-executor.5': attribute type 11 has an invalid length. netlink: 16 bytes leftover after parsing attributes in process `syz-executor.5'. warning: checkpointing journal with EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT can be slow netlink: 'syz-executor.5': attribute type 11 has an invalid length. netlink: 16 bytes leftover after parsing attributes in process `syz-executor.5'. warning: checkpointing journal with EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT can be slow Process accounting resumed Process accounting resumed Process accounting resumed Process accounting resumed Process accounting resumed Process accounting resumed Process accounting resumed