======================================
| [   12.995973][    C2] 1 lock held by swapper/2/0:
| [ 12.996179][ C2] #0: ffffffff963774c0 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2570) 
| [   12.996542][    C2]
| [   12.996542][    C2] stack backtrace:
[   12.996796][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   12.996798][    C2] Call Trace:
[   12.996801][    C2]  <IRQ>
[ 12.996803][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 12.996810][ C2] print_usage_bug.part.0 (kernel/locking/lockdep.c:4048) 
[ 12.996815][ C2] mark_lock_irq (kernel/locking/lockdep.c:4013 kernel/locking/lockdep.c:4059 kernel/locking/lockdep.c:4270) 
[ 12.996819][ C2] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 12.996825][ C2] ? save_trace (kernel/locking/lockdep.c:595) 
[ 12.996829][ C2] mark_lock (kernel/locking/lockdep.c:4756) 
[ 12.996833][ C2] mark_usage (kernel/locking/lockdep.c:4645) 
[ 12.996837][ C2] __lock_acquire (kernel/locking/lockdep.c:5194) 
[ 12.996840][ C2] ? __lock_acquire (kernel/locking/lockdep.c:5240) 
[ 12.996845][ C2] lock_acquire.part.0 (kernel/locking/lockdep.c:473 kernel/locking/lockdep.c:5873) 
[ 12.996848][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 12.996852][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 12.996858][ C2] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5834) 
[ 12.996861][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 12.996865][ C2] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 12.996868][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 12.996870][ C2] simple_pin_fs (fs/libfs.c:1067) 
[ 12.996874][ C2] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 12.996877][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 12.996883][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 12.996886][ 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) 
[ 12.996892][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 12.996895][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 12.996898][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 12.996901][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[ 12.996906][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 12.996911][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 12.996914][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 12.996916][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 12.996919][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 12.996924][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 12.996927][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 12.996930][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 12.996934][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 12.996943][ C2] __put_net (net/core/net_namespace.c:732) 
[ 12.996948][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 12.996952][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 12.996955][ C2] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 12.996960][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 12.996964][ C2] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 12.996967][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 12.996971][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 12.996975][ C2] rcu_core (kernel/rcu/tree.c:2834) 
[ 12.996981][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 12.996986][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 12.996990][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 12.996993][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[   12.996996][    C2]  </IRQ>
[   12.996997][    C2]  <TASK>
[ 12.996999][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 12.997002][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 12.997006][ 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
[   12.997008][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000242
[   12.997012][    C2] RAX: 000000000002f207 RBX: 1ffff92000028fc1 RCX: ffffffff953a35d9
[   12.997015][    C2] RDX: 0000000000000000 RSI: ffffffff95e9175c RDI: ffffffff95653ca0
[   12.997017][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c266fa
[   12.997019][    C2] R10: ffff8880361337d3 R11: ffffffff96011288 R12: 0000000000000000
[   12.997020][    C2] R13: ffff888001bf2300 R14: dffffc0000000000 R15: 0000000000000000
[ 12.997024][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 12.997029][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 12.997031][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 12.997034][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 12.997037][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 12.997041][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:60) 
[ 12.997047][ C2] do_idle (kernel/sched/idle.c:325) 
[ 12.997050][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 12.997054][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 12.997057][ C2] ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:233) 
[ 12.997062][ C2] common_startup_64 (arch/x86/kernel/head_64.S:419) 
| [   13.015059][    C2] RCU nest depth: 0, expected: 0
| [   13.015373][    C2] INFO: lockdep is turned off.
| [   13.015585][    C2] Preemption disabled at:
| [ 13.015587][ C2] 0x0 
[   13.015954][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.015956][    C2] Call Trace:
[   13.015958][    C2]  <IRQ>
[ 13.015960][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.015968][ C2] __might_resched (kernel/sched/core.c:8796) 
[ 13.015978][ C2] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 13.015983][ C2] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 13.015986][ C2] ? simple_recursive_removal (fs/libfs.c:614) 
[ 13.015991][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.015997][ 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) 
[ 13.016001][ C2] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:617) 
[ 13.016005][ 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) 
[ 13.016007][ C2] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 13.016014][ C2] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 13.016017][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 13.016023][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 13.016026][ 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) 
[ 13.016031][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.016035][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 13.016038][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 13.016044][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[ 13.016050][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.016054][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 13.016057][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 13.016060][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.016063][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.016067][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 13.016070][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.016072][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.016077][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 13.016084][ C2] __put_net (net/core/net_namespace.c:732) 
[ 13.016088][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 13.016092][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.016095][ C2] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.016100][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 13.016104][ C2] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 13.016109][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.016113][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 13.016119][ C2] rcu_core (kernel/rcu/tree.c:2834) 
[ 13.016124][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 13.016129][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 13.016132][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 13.016135][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[   13.016139][    C2]  </IRQ>
[   13.016140][    C2]  <TASK>
[ 13.016142][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.016145][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 13.016148][ 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
[   13.016151][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000242
[   13.016154][    C2] RAX: 000000000002f207 RBX: 1ffff92000028fc1 RCX: ffffffff953a35d9
[   13.016156][    C2] RDX: 0000000000000000 RSI: ffffffff95e9175c RDI: ffffffff95653ca0
[   13.016158][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c266fa
[   13.016160][    C2] R10: ffff8880361337d3 R11: ffffffff96011288 R12: 0000000000000000
[   13.016161][    C2] R13: ffff888001bf2300 R14: dffffc0000000000 R15: 0000000000000000
[ 13.016165][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 13.016170][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 13.016172][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.016175][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.016179][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 13.016183][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:60) 
[ 13.016188][ C2] do_idle (kernel/sched/idle.c:325) 
[ 13.016191][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.016195][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.016198][ 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