ceph: No mds server is up or the cluster is laggy
Increase LOCKDEP_CIRCULAR_QUEUE_BITS to avoid this warning:
------------[ cut here ]------------
lockdep bfs error:-1
WARNING: kernel/locking/lockdep.c:2075 at print_bfs_bug+0x7f/0xf0 kernel/locking/lockdep.c:2075, CPU#0: syz.4.2343/17634
Modules linked in:
CPU: 0 UID: 0 PID: 17634 Comm: syz.4.2343 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
RIP: 0010:print_bfs_bug+0x81/0xf0 kernel/locking/lockdep.c:2075
Code: 09 48 c7 c7 11 26 4e 8e e8 6c 13 e9 09 65 ff 0d 8d 90 a5 12 85 ed 74 17 83 fb ff 0f 84 b0 43 3b ff 48 8d 3d f1 90 61 0f 89 de <67> 48 0f b9 3a 5b 5d c3 cc cc cc cc 90 e8 2d 9e 3f 03 85 c0 74 1d
RSP: 0018:ffffc9000528f178 EFLAGS: 00010086
RAX: 000000000000003b RBX: 00000000ffffffff RCX: 0000000000000000
RDX: 000000000000003b RSI: 00000000ffffffff RDI: ffffffff91484750
RBP: 0000000000000001 R08: 0000000000000007 R09: 0000000000000000
R10: 8000000000000004 R11: fffffffffffdaf60 R12: ffffc9000528f1f0
R13: ffff88805a100c50 R14: ffffc9000528f230 R15: ffff88805a100c28
FS:  00007fa24d4766c0(0000) GS:ffff888123b60000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa24c5eb840 CR3: 000000002131f000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 check_irq_usage+0x32b/0x8b0 kernel/locking/lockdep.c:2832
 check_prev_add+0xfe/0xe60 kernel/locking/lockdep.c:3185
 check_prevs_add kernel/locking/lockdep.c:3300 [inline]
 validate_chain kernel/locking/lockdep.c:3924 [inline]
 __lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5254
 lock_acquire kernel/locking/lockdep.c:5908 [inline]
 lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:155 [inline]
 _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:181
 debug_object_activate+0x144/0x4b0 lib/debugobjects.c:873
 debug_hrtimer_activate kernel/time/hrtimer.c:486 [inline]
 debug_activate kernel/time/hrtimer.c:529 [inline]
 remove_and_enqueue_same_base kernel/time/hrtimer.c:1286 [inline]
 __hrtimer_start_range_ns kernel/time/hrtimer.c:1429 [inline]
 hrtimer_start_range_ns_common+0x53f/0x18b0 kernel/time/hrtimer.c:1508
 hrtimer_start_range_ns+0xc2/0x460 kernel/time/hrtimer.c:1530
 hrtimer_start include/linux/hrtimer.h:222 [inline]
 hrtick_cond_restart kernel/sched/core.c:949 [inline]
 hrtick_schedule_exit kernel/sched/core.c:1011 [inline]
 finish_lock_switch kernel/sched/core.c:5250 [inline]
 finish_task_switch.isra.0+0xa6e/0x10d0 kernel/sched/core.c:5369
 context_switch kernel/sched/core.c:5523 [inline]
 __schedule+0x1261/0x6920 kernel/sched/core.c:7270
 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:7592
 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline]
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
 irqentry_exit+0x205/0xa10 kernel/entry/common.c:167
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x5e/0x380 kernel/locking/lockdep.c:5913
Code: 05 4f dd a4 12 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 5e df 5d 0f 0f 82 c9 02 00 00 8b 35 fe 10 5e 0f 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 ed dc a4 12 0f 85 09 03 00 00 48 83 c4
RSP: 0018:ffffc9000528f928 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8e3c5247 RDI: ffffffff8c620e80
RBP: ffff888033bbe940 R08: 00000000002bb008 R09: ffffffff976b4258
R10: 0000000000000200 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000
 touch_wq_lockdep_map+0xad/0x1c0 kernel/workqueue.c:4111
 __flush_workqueue+0x131/0x1200 kernel/workqueue.c:4153
 drain_workqueue+0x175/0x3b0 kernel/workqueue.c:4317
 destroy_workqueue+0xc3/0xa30 kernel/workqueue.c:6155
 destroy_fs_client+0x170/0x3b0 fs/ceph/super.c:905
 ceph_kill_sb+0x2ec/0x9d0 fs/ceph/super.c:1607
 deactivate_locked_super+0xbd/0x140 fs/super.c:603
 ceph_get_tree+0x1534/0x1fd0 fs/ceph/super.c:1380
 vfs_get_tree+0x92/0x320 fs/super.c:1947
 vfs_cmd_create+0xd7/0x2a0 fs/fsopen.c:231
 vfs_fsconfig_locked fs/fsopen.c:295 [inline]
 __do_sys_fsconfig+0x55a/0xcb0 fs/fsopen.c:463
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa24c59e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa24d476028 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
RAX: ffffffffffffffda RBX: 00007fa24c825fa0 RCX: 00007fa24c59e159
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003
RBP: 00007fa24c635024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa24c826038 R14: 00007fa24c825fa0 R15: 00007fff112537d8
 </TASK>
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	48 c7 c7 11 26 4e 8e 	mov    $0xffffffff8e4e2611,%rdi
   7:	e8 6c 13 e9 09       	call   0x9e91378
   c:	65 ff 0d 8d 90 a5 12 	decl   %gs:0x12a5908d(%rip)        # 0x12a590a0
  13:	85 ed                	test   %ebp,%ebp
  15:	74 17                	je     0x2e
  17:	83 fb ff             	cmp    $0xffffffff,%ebx
  1a:	0f 84 b0 43 3b ff    	je     0xff3b43d0
  20:	48 8d 3d f1 90 61 0f 	lea    0xf6190f1(%rip),%rdi        # 0xf619118
  27:	89 de                	mov    %ebx,%esi
* 29:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2e:	5b                   	pop    %rbx
  2f:	5d                   	pop    %rbp
  30:	c3                   	ret
  31:	cc                   	int3
  32:	cc                   	int3
  33:	cc                   	int3
  34:	cc                   	int3
  35:	90                   	nop
  36:	e8 2d 9e 3f 03       	call   0x33f9e68
  3b:	85 c0                	test   %eax,%eax
  3d:	74 1d                	je     0x5c