======================================
| [   13.824189][    C2] 1 lock held by swapper/2/0:
| [ 13.824508][ C2] #0: ffffffff98f749c0 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2562) 
| [   13.825077][    C2]
| [   13.825077][    C2] stack backtrace:
[   13.825475][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.825479][    C2] Call Trace:
[   13.825481][    C2]  <IRQ>
[ 13.825485][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.825495][ C2] print_usage_bug.part.0 (kernel/locking/lockdep.c:4046) 
[ 13.825504][ C2] mark_lock_irq (kernel/locking/lockdep.c:4011 kernel/locking/lockdep.c:4057 kernel/locking/lockdep.c:4268) 
[ 13.825511][ C2] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 13.825519][ C2] ? save_trace (kernel/locking/lockdep.c:594) 
[ 13.825527][ C2] mark_lock (kernel/locking/lockdep.c:4754) 
[ 13.825534][ C2] mark_usage (kernel/locking/lockdep.c:4643) 
[ 13.825539][ C2] __lock_acquire (kernel/locking/lockdep.c:5189) 
[ 13.825548][ C2] lock_acquire.part.0 (kernel/locking/lockdep.c:472 kernel/locking/lockdep.c:5868) 
[ 13.825553][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.825560][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.825566][ C2] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5829) 
[ 13.825570][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.825578][ C2] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 13.825583][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.825588][ C2] simple_pin_fs (fs/libfs.c:1066) 
[ 13.825594][ C2] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 13.825601][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 13.825608][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 13.825613][ 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) 
[ 13.825619][ C2] ? rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2570) 
[ 13.825625][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 13.825630][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 13.825635][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[ 13.825641][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.825647][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:81) 
[ 13.825651][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:748) 
[ 13.825656][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.825660][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.825665][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 13.825669][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.825673][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.825678][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 13.825690][ C2] __put_net (net/core/net_namespace.c:732) 
[ 13.825695][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2366) 
[ 13.825702][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.825708][ C2] rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2570) 
[ 13.825715][ C2] ? find_held_lock (kernel/locking/lockdep.c:5348) 
[ 13.825723][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 13.825730][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 13.825736][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 13.825742][ C2] ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/preempt.h:104 ./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 13.825751][ C2] rcu_core (kernel/rcu/tree.c:2826) 
[ 13.825757][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 13.825767][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 13.825772][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 13.825777][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[   13.825783][    C2]  </IRQ>
[   13.825784][    C2]  <TASK>
[ 13.825787][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.825792][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:81) 
[ 13.825799][ 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
[   13.825804][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000242
[   13.825809][    C2] RAX: 0000000000038b07 RBX: 1ffff92000028fc1 RCX: ffffffff97f6ea19
[   13.825813][    C2] RDX: 0000000000000000 RSI: ffffffff98a89a45 RDI: ffffffff982513a0
[   13.825817][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c2667a
[   13.825819][    C2] R10: ffff8880361333d3 R11: 0000000000000000 R12: 0000000000000000
[   13.825822][    C2] R13: ffff888001bf2340 R14: dffffc0000000000 R15: 0000000000000000
[ 13.825830][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 13.825841][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:748) 
[ 13.825845][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.825849][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.825855][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 13.825862][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) 
[ 13.825870][ C2] do_idle (kernel/sched/idle.c:325) 
[ 13.825877][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.825882][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.825887][ C2] ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:233) 
[ 13.825897][ C2] common_startup_64 (arch/x86/kernel/head_64.S:419) 
| [   13.854355][    C2] RCU nest depth: 0, expected: 0
| [   13.854682][    C2] INFO: lockdep is turned off.
| [   13.855203][    C2] Preemption disabled at:
| [ 13.855206][ C2] 0x0 
[   13.855782][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.855785][    C2] Call Trace:
[   13.855788][    C2]  <IRQ>
[ 13.855792][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.855804][ C2] __might_resched (kernel/sched/core.c:8819) 
[ 13.855814][ C2] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 13.855820][ C2] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 13.855824][ C2] ? simple_recursive_removal (./include/linux/dcache.h:345 fs/libfs.c:610) 
[ 13.855831][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.855838][ 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) 
[ 13.855846][ C2] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:616) 
[ 13.855851][ C2] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 13.855858][ 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) 
[ 13.855867][ C2] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 13.855872][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 13.855881][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 13.855886][ 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) 
[ 13.855893][ C2] ? rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2570) 
[ 13.855899][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 13.855905][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 13.855910][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[ 13.855916][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.855921][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:81) 
[ 13.855926][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:748) 
[ 13.855930][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.855934][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.855939][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 13.855943][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.855947][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.855952][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 13.855963][ C2] __put_net (net/core/net_namespace.c:732) 
[ 13.855968][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2366) 
[ 13.855975][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.855981][ C2] rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2570) 
[ 13.855988][ C2] ? find_held_lock (kernel/locking/lockdep.c:5348) 
[ 13.855996][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 13.856003][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 13.856010][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 13.856015][ C2] ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/preempt.h:104 ./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 13.856024][ C2] rcu_core (kernel/rcu/tree.c:2826) 
[ 13.856031][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 13.856040][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 13.856044][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 13.856048][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[   13.856053][    C2]  </IRQ>
[   13.856056][    C2]  <TASK>
[ 13.856058][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.856064][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:81) 
[ 13.856070][ 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
[   13.856075][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000242
[   13.856081][    C2] RAX: 0000000000038b07 RBX: 1ffff92000028fc1 RCX: ffffffff97f6ea19
[   13.856085][    C2] RDX: 0000000000000000 RSI: ffffffff98a89a45 RDI: ffffffff982513a0
[   13.856088][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c2667a
[   13.856092][    C2] R10: ffff8880361333d3 R11: 0000000000000000 R12: 0000000000000000
[   13.856094][    C2] R13: ffff888001bf2340 R14: dffffc0000000000 R15: 0000000000000000
[ 13.856103][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 13.856113][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:748) 
[ 13.856117][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 13.856122][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 13.856127][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 13.856134][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) 
[ 13.856143][ C2] do_idle (kernel/sched/idle.c:325) 
[ 13.856148][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 13.856153][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 13.856156][ 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