======================================
| [   13.855625][    C2] 1 lock held by swapper/2/0:
| [ 13.855837][ C2] #0: ffffffff869774c0 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2570) 
| [   13.856231][    C2]
| [   13.856231][    C2] stack backtrace:
[   13.856512][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.856514][    C2] Call Trace:
[   13.856519][    C2]  <IRQ>
[ 13.856521][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.856530][ C2] print_usage_bug.part.0 (kernel/locking/lockdep.c:4048) 
[ 13.856537][ C2] mark_lock_irq (kernel/locking/lockdep.c:4013 kernel/locking/lockdep.c:4059 kernel/locking/lockdep.c:4270) 
[ 13.856541][ C2] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 13.856547][ C2] ? save_trace (kernel/locking/lockdep.c:595) 
[ 13.856552][ C2] mark_lock (kernel/locking/lockdep.c:4756) 
[ 13.856558][ C2] mark_usage (kernel/locking/lockdep.c:4645) 
[ 13.856563][ C2] __lock_acquire (kernel/locking/lockdep.c:5194) 
[ 13.856567][ C2] ? __lock_acquire (kernel/locking/lockdep.c:5240) 
[ 13.856571][ C2] lock_acquire.part.0 (kernel/locking/lockdep.c:473 kernel/locking/lockdep.c:5873) 
[ 13.856575][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 13.856580][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.856587][ C2] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5834) 
[ 13.856590][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 13.856593][ C2] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 13.856598][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 13.856600][ C2] simple_pin_fs (fs/libfs.c:1067) 
[ 13.856604][ C2] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 13.856609][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 13.856617][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 13.856620][ 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) 
[ 13.856629][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.856632][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 13.856635][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 13.856640][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[ 13.856644][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.856652][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 13.856655][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 13.856658][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.856660][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.856667][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 13.856670][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.856673][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.856677][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 13.856690][ C2] __put_net (net/core/net_namespace.c:732) 
[ 13.856697][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 13.856701][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.856704][ C2] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.856707][ C2] ? find_held_lock (kernel/locking/lockdep.c:5353) 
[ 13.856711][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 13.856714][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 13.856718][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 13.856722][ C2] ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/preempt.h:104 ./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 13.856727][ C2] rcu_core (kernel/rcu/tree.c:2834) 
[ 13.856733][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 13.856738][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 13.856741][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 13.856745][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[   13.856748][    C2]  </IRQ>
[   13.856749][    C2]  <TASK>
[ 13.856751][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.856754][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 13.856758][ 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
[   13.856760][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000246
[   13.856768][    C2] RAX: 000000000003bc0f RBX: 1ffff92000028fc1 RCX: ffffffff859a35d9
[   13.856770][    C2] RDX: 0000000000000000 RSI: ffffffff8649175c RDI: ffffffff85c53ca0
[   13.856772][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1005ea66fa
[   13.856773][    C2] R10: ffff88802f5337d3 R11: ffffffff86611288 R12: 0000000000000000
[   13.856775][    C2] R13: ffff888001bf2300 R14: dffffc0000000000 R15: 0000000000000000
[ 13.856780][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 13.856785][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 13.856787][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.856790][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.856794][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 13.856798][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:60) 
[ 13.856803][ C2] do_idle (kernel/sched/idle.c:325) 
[ 13.856806][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.856810][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.856813][ C2] ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:233) 
[ 13.856818][ C2] common_startup_64 (arch/x86/kernel/head_64.S:419) 
| [   13.874846][    C2] RCU nest depth: 0, expected: 0
| [   13.875048][    C2] INFO: lockdep is turned off.
| [   13.875360][    C2] Preemption disabled at:
| [ 13.875362][ C2] 0x0 
[   13.875734][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.875736][    C2] Call Trace:
[   13.875738][    C2]  <IRQ>
[ 13.875741][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.875748][ C2] __might_resched (kernel/sched/core.c:8796) 
[ 13.875762][ C2] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 13.875767][ C2] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 13.875770][ C2] ? simple_recursive_removal (fs/libfs.c:614) 
[ 13.875774][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.875780][ 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) 
[ 13.875784][ C2] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:617) 
[ 13.875787][ 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) 
[ 13.875789][ C2] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 13.875795][ C2] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 13.875798][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 13.875803][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 13.875806][ 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) 
[ 13.875811][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.875815][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 13.875817][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 13.875822][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[ 13.875827][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.875830][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 13.875834][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 13.875836][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.875838][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.875843][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 13.875845][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.875848][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.875852][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 13.875860][ C2] __put_net (net/core/net_namespace.c:732) 
[ 13.875864][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 13.875868][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.875871][ C2] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.875875][ C2] ? find_held_lock (kernel/locking/lockdep.c:5353) 
[ 13.875878][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 13.875882][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 13.875886][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 13.875890][ C2] ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/preempt.h:104 ./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 13.875895][ C2] rcu_core (kernel/rcu/tree.c:2834) 
[ 13.875900][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 13.875905][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 13.875909][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 13.875912][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[   13.875915][    C2]  </IRQ>
[   13.875916][    C2]  <TASK>
[ 13.875918][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.875921][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 13.875925][ 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
[   13.875927][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000246
[   13.875930][    C2] RAX: 000000000003bc0f RBX: 1ffff92000028fc1 RCX: ffffffff859a35d9
[   13.875932][    C2] RDX: 0000000000000000 RSI: ffffffff8649175c RDI: ffffffff85c53ca0
[   13.875934][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1005ea66fa
[   13.875936][    C2] R10: ffff88802f5337d3 R11: ffffffff86611288 R12: 0000000000000000
[   13.875938][    C2] R13: ffff888001bf2300 R14: dffffc0000000000 R15: 0000000000000000
[ 13.875941][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 13.875946][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 13.875948][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.875951][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.875954][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 13.875958][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:60) 
[ 13.875963][ C2] do_idle (kernel/sched/idle.c:325) 
[ 13.875967][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.875970][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.875973][ 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