======================================
| [   13.811839][    C2] 1 lock held by swapper/2/0:
| [ 13.812032][ C2] #0: ffffffffbc1749c0 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2562) 
| [   13.812377][    C2]
| [   13.812377][    C2] stack backtrace:
[   13.812628][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.812631][    C2] Call Trace:
[   13.812634][    C2]  <IRQ>
[ 13.812637][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.812646][ C2] print_usage_bug.part.0 (kernel/locking/lockdep.c:4046) 
[ 13.812653][ C2] mark_lock_irq (kernel/locking/lockdep.c:4011 kernel/locking/lockdep.c:4057 kernel/locking/lockdep.c:4268) 
[ 13.812660][ C2] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 13.812667][ C2] ? save_trace (kernel/locking/lockdep.c:594) 
[ 13.812676][ C2] mark_lock (kernel/locking/lockdep.c:4754) 
[ 13.812682][ C2] mark_usage (kernel/locking/lockdep.c:4643) 
[ 13.812688][ C2] __lock_acquire (kernel/locking/lockdep.c:5189) 
[ 13.812695][ C2] lock_acquire.part.0 (kernel/locking/lockdep.c:472 kernel/locking/lockdep.c:5868) 
[ 13.812698][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.812703][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.812706][ C2] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5829) 
[ 13.812709][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.812713][ C2] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 13.812716][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.812719][ C2] simple_pin_fs (fs/libfs.c:1066) 
[ 13.812722][ C2] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 13.812726][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 13.812732][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 13.812736][ 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:2366) 
[ 13.812740][ C2] ? rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2570) 
[ 13.812744][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 13.812748][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 13.812751][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[ 13.812755][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.812758][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:81) 
[ 13.812762][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:748) 
[ 13.812764][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.812766][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.812769][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 13.812772][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.812774][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.812777][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 13.812783][ C2] __put_net (net/core/net_namespace.c:732) 
[ 13.812787][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2366) 
[ 13.812791][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.812794][ C2] rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2570) 
[ 13.812799][ C2] ? find_held_lock (kernel/locking/lockdep.c:5348) 
[ 13.812803][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 13.812807][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 13.812811][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 13.812814][ C2] ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/preempt.h:104 ./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 13.812819][ C2] rcu_core (kernel/rcu/tree.c:2826) 
[ 13.812822][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 13.812827][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 13.812830][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 13.812833][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[   13.812836][    C2]  </IRQ>
[   13.812838][    C2]  <TASK>
[ 13.812839][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.812842][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:81) 
[ 13.812846][ C2] Code: 50 b7 00 e9 c3 57 02 00 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 c3 45 12 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
All code
========
   0:	50                   	push   %rax
   1:	b7 00                	mov    $0x0,%bh
   3:	e9 c3 57 02 00       	jmp    0x257cb
   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 c3 45 12 00 	verw   0x1245c3(%rip)        # 0x1245eb
  28:	fb                   	sti
  29:	f4                   	hlt
  2a:*	c3                   	ret		<-- trapping instruction
  2b:	cc                   	int3
  2c:	cc                   	int3
  2d:	cc                   	int3
  2e:	cc                   	int3
  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:	c3                   	ret
   1:	cc                   	int3
   2:	cc                   	int3
   3:	cc                   	int3
   4:	cc                   	int3
   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
[   13.812849][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000242
[   13.812852][    C2] RAX: 000000000004138f RBX: 1ffff92000028fc1 RCX: ffffffffbb16ea19
[   13.812854][    C2] RDX: 0000000000000000 RSI: ffffffffbbc89a45 RDI: ffffffffbb4513a0
[   13.812856][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c2667a
[   13.812858][    C2] R10: ffff8880361333d3 R11: 0000000000000000 R12: 0000000000000000
[   13.812860][    C2] R13: ffff888001bf2340 R14: dffffc0000000000 R15: 0000000000000000
[ 13.812864][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 13.812869][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:748) 
[ 13.812871][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.812874][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.812877][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 13.812880][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) 
[ 13.812885][ C2] do_idle (kernel/sched/idle.c:325) 
[ 13.812888][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.812891][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.812894][ C2] ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:233) 
[ 13.812898][ C2] common_startup_64 (arch/x86/kernel/head_64.S:419) 
| [   13.832694][    C2] RCU nest depth: 0, expected: 0
| [   13.832929][    C2] INFO: lockdep is turned off.
| [   13.833184][    C2] Preemption disabled at:
| [ 13.833186][ C2] 0x0 
[   13.833596][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.833598][    C2] Call Trace:
[   13.833600][    C2]  <IRQ>
[ 13.833602][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.833611][ C2] __might_resched (kernel/sched/core.c:8819) 
[ 13.833622][ C2] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 13.833628][ C2] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 13.833632][ C2] ? simple_recursive_removal (./include/linux/dcache.h:345 fs/libfs.c:610) 
[ 13.833638][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.833643][ 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) 
[ 13.833648][ C2] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:616) 
[ 13.833651][ C2] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 13.833656][ 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) 
[ 13.833661][ C2] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 13.833664][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 13.833670][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 13.833673][ 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:2366) 
[ 13.833679][ C2] ? rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2570) 
[ 13.833683][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 13.833686][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 13.833691][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[ 13.833695][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.833698][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:81) 
[ 13.833702][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:748) 
[ 13.833704][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.833706][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.833710][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 13.833712][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.833714][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.833718][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 13.833724][ C2] __put_net (net/core/net_namespace.c:732) 
[ 13.833728][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2366) 
[ 13.833732][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.833735][ C2] rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2570) 
[ 13.833739][ C2] ? find_held_lock (kernel/locking/lockdep.c:5348) 
[ 13.833745][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 13.833749][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 13.833754][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 13.833757][ C2] ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/preempt.h:104 ./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 13.833762][ C2] rcu_core (kernel/rcu/tree.c:2826) 
[ 13.833766][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 13.833771][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 13.833774][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 13.833776][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[   13.833780][    C2]  </IRQ>
[   13.833781][    C2]  <TASK>
[ 13.833783][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.833786][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:81) 
[ 13.833790][ C2] Code: 50 b7 00 e9 c3 57 02 00 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 c3 45 12 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
All code
========
   0:	50                   	push   %rax
   1:	b7 00                	mov    $0x0,%bh
   3:	e9 c3 57 02 00       	jmp    0x257cb
   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 c3 45 12 00 	verw   0x1245c3(%rip)        # 0x1245eb
  28:	fb                   	sti
  29:	f4                   	hlt
  2a:*	c3                   	ret		<-- trapping instruction
  2b:	cc                   	int3
  2c:	cc                   	int3
  2d:	cc                   	int3
  2e:	cc                   	int3
  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:	c3                   	ret
   1:	cc                   	int3
   2:	cc                   	int3
   3:	cc                   	int3
   4:	cc                   	int3
   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
[   13.833792][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000242
[   13.833796][    C2] RAX: 000000000004138f RBX: 1ffff92000028fc1 RCX: ffffffffbb16ea19
[   13.833798][    C2] RDX: 0000000000000000 RSI: ffffffffbbc89a45 RDI: ffffffffbb4513a0
[   13.833800][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c2667a
[   13.833802][    C2] R10: ffff8880361333d3 R11: 0000000000000000 R12: 0000000000000000
[   13.833804][    C2] R13: ffff888001bf2340 R14: dffffc0000000000 R15: 0000000000000000
[ 13.833808][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 13.833813][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:748) 
[ 13.833816][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.833818][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.833821][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 13.833825][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) 
[ 13.833829][ C2] do_idle (kernel/sched/idle.c:325) 
[ 13.833832][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.833835][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.833838][ 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