======================================
| [   15.840037][    C2] 1 lock held by swapper/2/0:
| [ 15.840398][ C2] #0: ffffffff9b9774c0 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2570) 
| [   15.840958][    C2]
| [   15.840958][    C2] stack backtrace:
[   15.841353][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   15.841357][    C2] Call Trace:
[   15.841360][    C2]  <IRQ>
[ 15.841364][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 15.841373][ C2] print_usage_bug.part.0 (kernel/locking/lockdep.c:4048) 
[ 15.841383][ C2] mark_lock_irq (kernel/locking/lockdep.c:4013 kernel/locking/lockdep.c:4059 kernel/locking/lockdep.c:4270) 
[ 15.841389][ C2] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 15.841397][ C2] ? save_trace (kernel/locking/lockdep.c:595) 
[ 15.841404][ C2] mark_lock (kernel/locking/lockdep.c:4756) 
[ 15.841411][ C2] mark_usage (kernel/locking/lockdep.c:4645) 
[ 15.841417][ C2] __lock_acquire (kernel/locking/lockdep.c:5194) 
[ 15.841423][ C2] ? __lock_acquire (kernel/locking/lockdep.c:5240) 
[ 15.841431][ C2] lock_acquire.part.0 (kernel/locking/lockdep.c:473 kernel/locking/lockdep.c:5873) 
[ 15.841437][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 15.841444][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 15.841450][ C2] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5834) 
[ 15.841455][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 15.841462][ C2] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 15.841468][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 15.841473][ C2] simple_pin_fs (fs/libfs.c:1067) 
[ 15.841478][ C2] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 15.841485][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 15.841492][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 15.841497][ C2] ? __sk_destruct (./include/linux/instrumented.h:96 ./include/linux/atomic/atomic-instrumented.h:400 ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 ./include/net/net_namespace.h:287 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 15.841504][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 15.841509][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 15.841513][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 15.841519][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[ 15.841526][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 15.841532][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 15.841537][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 15.841541][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 15.841545][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 15.841551][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 15.841554][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 15.841558][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 15.841562][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 15.841573][ C2] __put_net (net/core/net_namespace.c:732) 
[ 15.841579][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 15.841586][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 15.841590][ C2] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 15.841596][ C2] ? find_held_lock (kernel/locking/lockdep.c:5353) 
[ 15.841602][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 15.841607][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 15.841611][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 15.841616][ C2] ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/preempt.h:104 ./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 15.841624][ C2] rcu_core (kernel/rcu/tree.c:2834) 
[ 15.841632][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 15.841642][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 15.841648][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 15.841653][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[   15.841659][    C2]  </IRQ>
[   15.841661][    C2]  <TASK>
[ 15.841664][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 15.841669][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 15.841675][ C2] Code: 92 b4 00 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 83 07 0f 00 fb f4 <e9> fc 54 02 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
All code
========
   0:	92                   	xchg   %eax,%edx
   1:	b4 00                	mov    $0x0,%ah
   3:	c3                   	ret
   4:	cc                   	int3
   5:	cc                   	int3
   6:	cc                   	int3
   7:	cc                   	int3
   8:	0f 1f 00             	nopl   (%rax)
   b:	90                   	nop
   c:	90                   	nop
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	f3 0f 1e fa          	endbr64
  1f:	66 90                	xchg   %ax,%ax
  21:	0f 00 2d 83 07 0f 00 	verw   0xf0783(%rip)        # 0xf07ab
  28:	fb                   	sti
  29:	f4                   	hlt
  2a:*	e9 fc 54 02 00       	jmp    0x2552b		<-- trapping instruction
  2f:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
  36:	00 00 00 
  39:	66 90                	xchg   %ax,%ax
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop

Code starting with the faulting instruction
===========================================
   0:	e9 fc 54 02 00       	jmp    0x25501
   5:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
   c:	00 00 00 
   f:	66 90                	xchg   %ax,%ax
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
[   15.841679][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000242
[   15.841684][    C2] RAX: 00000000000398a1 RBX: 1ffff92000028fc1 RCX: ffffffff9a9a35d9
[   15.841687][    C2] RDX: 0000000000000000 RSI: ffffffff9b49175c RDI: ffffffff9ac53ca0
[   15.841690][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c266fa
[   15.841692][    C2] R10: ffff8880361337d3 R11: ffffffff9b611288 R12: 0000000000000000
[   15.841695][    C2] R13: ffff888001bf2300 R14: dffffc0000000000 R15: 0000000000000000
[ 15.841701][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 15.841707][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 15.841712][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 15.841716][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 15.841723][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 15.841730][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:60) 
[ 15.841738][ C2] do_idle (kernel/sched/idle.c:325) 
[ 15.841745][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 15.841751][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 15.841756][ C2] ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:233) 
[ 15.841765][ C2] common_startup_64 (arch/x86/kernel/head_64.S:419) 
| [   15.865982][    C2] RCU nest depth: 0, expected: 0
| [   15.866298][    C2] INFO: lockdep is turned off.
| [   15.866504][    C2] Preemption disabled at:
| [ 15.866506][ C2] 0x0 
[   15.866899][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   15.866901][    C2] Call Trace:
[   15.866903][    C2]  <IRQ>
[ 15.866906][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 15.866914][ C2] __might_resched (kernel/sched/core.c:8796) 
[ 15.866923][ C2] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 15.866927][ C2] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 15.866930][ C2] ? simple_recursive_removal (fs/libfs.c:614) 
[ 15.866935][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 15.866941][ C2] ? do_raw_spin_unlock (./arch/x86/include/asm/atomic.h:23 ./include/linux/atomic/atomic-arch-fallback.h:457 ./include/linux/atomic/atomic-instrumented.h:33 ./include/asm-generic/qspinlock.h:57 kernel/locking/spinlock_debug.c:101 kernel/locking/spinlock_debug.c:141) 
[ 15.866945][ C2] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:617) 
[ 15.866948][ C2] ? do_raw_spin_unlock (./arch/x86/include/asm/atomic.h:23 ./include/linux/atomic/atomic-arch-fallback.h:457 ./include/linux/atomic/atomic-instrumented.h:33 ./include/asm-generic/qspinlock.h:57 kernel/locking/spinlock_debug.c:101 kernel/locking/spinlock_debug.c:141) 
[ 15.866951][ C2] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 15.866957][ C2] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 15.866960][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 15.866965][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 15.866968][ C2] ? __sk_destruct (./include/linux/instrumented.h:96 ./include/linux/atomic/atomic-instrumented.h:400 ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 ./include/net/net_namespace.h:287 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 15.866973][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 15.866978][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 15.866980][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 15.866986][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[ 15.866991][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 15.866995][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 15.866998][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 15.867001][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 15.867003][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 15.867007][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 15.867010][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 15.867013][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 15.867017][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 15.867024][ C2] __put_net (net/core/net_namespace.c:732) 
[ 15.867028][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 15.867032][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 15.867035][ C2] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 15.867039][ C2] ? find_held_lock (kernel/locking/lockdep.c:5353) 
[ 15.867043][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 15.867047][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 15.867052][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 15.867055][ C2] ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/preempt.h:104 ./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 15.867060][ C2] rcu_core (kernel/rcu/tree.c:2834) 
[ 15.867065][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 15.867070][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 15.867074][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 15.867077][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[   15.867080][    C2]  </IRQ>
[   15.867082][    C2]  <TASK>
[ 15.867083][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 15.867086][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 15.867090][ C2] Code: 92 b4 00 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 83 07 0f 00 fb f4 <e9> fc 54 02 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
All code
========
   0:	92                   	xchg   %eax,%edx
   1:	b4 00                	mov    $0x0,%ah
   3:	c3                   	ret
   4:	cc                   	int3
   5:	cc                   	int3
   6:	cc                   	int3
   7:	cc                   	int3
   8:	0f 1f 00             	nopl   (%rax)
   b:	90                   	nop
   c:	90                   	nop
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	f3 0f 1e fa          	endbr64
  1f:	66 90                	xchg   %ax,%ax
  21:	0f 00 2d 83 07 0f 00 	verw   0xf0783(%rip)        # 0xf07ab
  28:	fb                   	sti
  29:	f4                   	hlt
  2a:*	e9 fc 54 02 00       	jmp    0x2552b		<-- trapping instruction
  2f:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
  36:	00 00 00 
  39:	66 90                	xchg   %ax,%ax
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop

Code starting with the faulting instruction
===========================================
   0:	e9 fc 54 02 00       	jmp    0x25501
   5:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
   c:	00 00 00 
   f:	66 90                	xchg   %ax,%ax
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
[   15.867092][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000242
[   15.867096][    C2] RAX: 00000000000398a1 RBX: 1ffff92000028fc1 RCX: ffffffff9a9a35d9
[   15.867098][    C2] RDX: 0000000000000000 RSI: ffffffff9b49175c RDI: ffffffff9ac53ca0
[   15.867100][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c266fa
[   15.867101][    C2] R10: ffff8880361337d3 R11: ffffffff9b611288 R12: 0000000000000000
[   15.867103][    C2] R13: ffff888001bf2300 R14: dffffc0000000000 R15: 0000000000000000
[ 15.867107][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 15.867111][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 15.867114][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 15.867116][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 15.867120][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 15.867124][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:60) 
[ 15.867128][ C2] do_idle (kernel/sched/idle.c:325) 
[ 15.867132][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 15.867135][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 15.867138][ C2] ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:233) 


Finger prints:
__might_resched:down_write:simple_recursive_removal:debugfs_remove:ref_tracker_dir_exit
mark_lock_irq:mark_lock:mark_usage:__lock_acquire:_raw_spin_lock