======================================
| [   12.470250][    C2] 1 lock held by swapper/2/0:
| [ 12.470454][ C2] #0: ffffffff933774c0 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2570) 
| [   12.470816][    C2]
| [   12.470816][    C2] stack backtrace:
[   12.471069][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   12.471071][    C2] Call Trace:
[   12.471073][    C2]  <IRQ>
[ 12.471075][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 12.471081][ C2] print_usage_bug.part.0 (kernel/locking/lockdep.c:4048) 
[ 12.471085][ C2] mark_lock_irq (kernel/locking/lockdep.c:4013 kernel/locking/lockdep.c:4059 kernel/locking/lockdep.c:4270) 
[ 12.471090][ C2] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 12.471095][ C2] ? save_trace (kernel/locking/lockdep.c:595) 
[ 12.471099][ C2] mark_lock (kernel/locking/lockdep.c:4756) 
[ 12.471103][ C2] mark_usage (kernel/locking/lockdep.c:4645) 
[ 12.471106][ C2] __lock_acquire (kernel/locking/lockdep.c:5194) 
[ 12.471109][ C2] ? __lock_acquire (kernel/locking/lockdep.c:5240) 
[ 12.471114][ C2] lock_acquire.part.0 (kernel/locking/lockdep.c:473 kernel/locking/lockdep.c:5873) 
[ 12.471117][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 12.471120][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 12.471125][ C2] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5834) 
[ 12.471128][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 12.471131][ C2] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 12.471135][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 12.471137][ C2] simple_pin_fs (fs/libfs.c:1067) 
[ 12.471140][ C2] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 12.471144][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:411 lib/ref_tracker.c:195) 
[ 12.471148][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 12.471151][ 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) 
[ 12.471156][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 12.471159][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 12.471162][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 12.471165][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[ 12.471169][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 12.471172][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 12.471175][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 12.471178][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 12.471180][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 12.471183][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 12.471186][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 12.471188][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 12.471192][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 12.471199][ C2] __put_net (net/core/net_namespace.c:732) 
[ 12.471203][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 12.471207][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 12.471210][ C2] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 12.471215][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 12.471218][ C2] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 12.471222][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 12.471225][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 12.471230][ C2] rcu_core (kernel/rcu/tree.c:2834) 
[ 12.471234][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 12.471240][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 12.471243][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 12.471247][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[   12.471251][    C2]  </IRQ>
[   12.471252][    C2]  <TASK>
[ 12.471253][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 12.471256][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 12.471260][ C2] Code: a2 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 17 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:	a2 b4 00 c3 cc cc cc 	movabs %al,0xfccccccccc300b4
   7:	cc 0f 
   9:	1f                   	(bad)
   a:	00 90 90 90 90 90    	add    %dl,-0x6f6f6f70(%rax)
  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 17 0f 00 	verw   0xf1783(%rip)        # 0xf17ab
  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
[   12.471263][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000242
[   12.471265][    C2] RAX: 000000000003a637 RBX: 1ffff92000028fc1 RCX: ffffffff923a25d9
[   12.471268][    C2] RDX: 0000000000000000 RSI: ffffffff92e9175c RDI: ffffffff92653ca0
[   12.471269][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1005ee66fa
[   12.471271][    C2] R10: ffff88802f7337d3 R11: ffffffff93011288 R12: 0000000000000000
[   12.471273][    C2] R13: ffff888001bf2300 R14: dffffc0000000000 R15: 0000000000000000
[ 12.471276][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 12.471281][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 12.471284][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 12.471286][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 12.471289][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 12.471293][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:60) 
[ 12.471298][ C2] do_idle (kernel/sched/idle.c:325) 
[ 12.471302][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 12.471305][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 12.471308][ C2] ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:233) 
[ 12.471313][ C2] common_startup_64 (arch/x86/kernel/head_64.S:419) 
| [   12.486993][    C2] RCU nest depth: 0, expected: 0
| [   12.487180][    C2] INFO: lockdep is turned off.
| [   12.487372][    C2] Preemption disabled at:
| [ 12.487374][ C2] 0x0 
[   12.487709][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   12.487711][    C2] Call Trace:
[   12.487713][    C2]  <IRQ>
[ 12.487715][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 12.487722][ C2] __might_resched (kernel/sched/core.c:8796) 
[ 12.487730][ C2] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 12.487734][ C2] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 12.487737][ C2] ? simple_recursive_removal (fs/libfs.c:614) 
[ 12.487741][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 12.487746][ 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) 
[ 12.487750][ C2] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:617) 
[ 12.487753][ 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) 
[ 12.487755][ C2] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 12.487761][ C2] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 12.487764][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:411 lib/ref_tracker.c:195) 
[ 12.487769][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 12.487771][ 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) 
[ 12.487776][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 12.487780][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 12.487782][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 12.487788][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[ 12.487792][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 12.487796][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 12.487799][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 12.487802][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 12.487804][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 12.487808][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 12.487811][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 12.487813][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 12.487817][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 12.487824][ C2] __put_net (net/core/net_namespace.c:732) 
[ 12.487828][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 12.487832][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 12.487835][ C2] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 12.487840][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 12.487843][ C2] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 12.487848][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 12.487851][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 12.487856][ C2] rcu_core (kernel/rcu/tree.c:2834) 
[ 12.487861][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 12.487866][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 12.487870][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 12.487873][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[   12.487876][    C2]  </IRQ>
[   12.487877][    C2]  <TASK>
[ 12.487879][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 12.487882][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:82) 
[ 12.487886][ C2] Code: a2 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 17 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:	a2 b4 00 c3 cc cc cc 	movabs %al,0xfccccccccc300b4
   7:	cc 0f 
   9:	1f                   	(bad)
   a:	00 90 90 90 90 90    	add    %dl,-0x6f6f6f70(%rax)
  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 17 0f 00 	verw   0xf1783(%rip)        # 0xf17ab
  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
[   12.487888][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000242
[   12.487892][    C2] RAX: 000000000003a637 RBX: 1ffff92000028fc1 RCX: ffffffff923a25d9
[   12.487894][    C2] RDX: 0000000000000000 RSI: ffffffff92e9175c RDI: ffffffff92653ca0
[   12.487895][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1005ee66fa
[   12.487897][    C2] R10: ffff88802f7337d3 R11: ffffffff93011288 R12: 0000000000000000
[   12.487899][    C2] R13: ffff888001bf2300 R14: dffffc0000000000 R15: 0000000000000000
[ 12.487903][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 12.487907][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:743) 
[ 12.487910][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 12.487912][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 12.487916][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 12.487919][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:60) 
[ 12.487924][ C2] do_idle (kernel/sched/idle.c:325) 
[ 12.487928][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 12.487931][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 12.487934][ 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