======================================
| [   12.573252][    C2] 1 lock held by swapper/2/0:
| [ 12.573442][ C2] #0: ffffffff909749c0 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2562) 
| [   12.573785][    C2]
| [   12.573785][    C2] stack backtrace:
[   12.574042][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   12.574044][    C2] Call Trace:
[   12.574045][    C2]  <IRQ>
[ 12.574048][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 12.574054][ C2] print_usage_bug.part.0 (kernel/locking/lockdep.c:4046) 
[ 12.574058][ C2] mark_lock_irq (kernel/locking/lockdep.c:4011 kernel/locking/lockdep.c:4057 kernel/locking/lockdep.c:4268) 
[ 12.574062][ C2] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 12.574067][ C2] ? save_trace (kernel/locking/lockdep.c:594) 
[ 12.574072][ C2] mark_lock (kernel/locking/lockdep.c:4754) 
[ 12.574076][ C2] mark_usage (kernel/locking/lockdep.c:4643) 
[ 12.574079][ C2] __lock_acquire (kernel/locking/lockdep.c:5189) 
[ 12.574083][ C2] lock_acquire.part.0 (kernel/locking/lockdep.c:472 kernel/locking/lockdep.c:5868) 
[ 12.574086][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 12.574090][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 12.574094][ C2] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5829) 
[ 12.574096][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 12.574100][ C2] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 12.574103][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 12.574105][ C2] simple_pin_fs (fs/libfs.c:1066) 
[ 12.574109][ C2] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 12.574113][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 12.574119][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 12.574122][ 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) 
[ 12.574127][ C2] ? rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2570) 
[ 12.574130][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 12.574133][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 12.574136][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[ 12.574140][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 12.574143][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:81) 
[ 12.574147][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:748) 
[ 12.574149][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 12.574151][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 12.574155][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 12.574157][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 12.574159][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 12.574162][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 12.574169][ C2] __put_net (net/core/net_namespace.c:732) 
[ 12.574172][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2366) 
[ 12.574176][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 12.574179][ C2] rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2570) 
[ 12.574184][ C2] ? find_held_lock (kernel/locking/lockdep.c:5348) 
[ 12.574188][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 12.574192][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 12.574196][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 12.574199][ C2] ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/preempt.h:104 ./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 12.574204][ C2] rcu_core (kernel/rcu/tree.c:2826) 
[ 12.574207][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 12.574213][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 12.574215][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 12.574218][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[   12.574221][    C2]  </IRQ>
[   12.574222][    C2]  <TASK>
[ 12.574224][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 12.574227][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:81) 
[ 12.574231][ 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
[   12.574234][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000246
[   12.574237][    C2] RAX: 00000000000311dd RBX: 1ffff92000028fc1 RCX: ffffffff8f96ea19
[   12.574239][    C2] RDX: 0000000000000000 RSI: ffffffff90489a45 RDI: ffffffff8fc513a0
[   12.574240][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c2667a
[   12.574242][    C2] R10: ffff8880361333d3 R11: 0000000000000000 R12: 0000000000000000
[   12.574244][    C2] R13: ffff888001bf2340 R14: dffffc0000000000 R15: 0000000000000000
[ 12.574248][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 12.574254][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:748) 
[ 12.574256][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 12.574258][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 12.574261][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 12.574265][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) 
[ 12.574269][ C2] do_idle (kernel/sched/idle.c:325) 
[ 12.574272][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 12.574275][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 12.574278][ C2] ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:233) 
[ 12.574282][ C2] common_startup_64 (arch/x86/kernel/head_64.S:419) 
| [   12.590141][    C2] RCU nest depth: 0, expected: 0
| [   12.590329][    C2] INFO: lockdep is turned off.
| [   12.590528][    C2] Preemption disabled at:
| [ 12.590530][ C2] 0x0 
[   12.590882][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   12.590884][    C2] Call Trace:
[   12.590885][    C2]  <IRQ>
[ 12.590887][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 12.590895][ C2] __might_resched (kernel/sched/core.c:8819) 
[ 12.590901][ C2] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 12.590905][ C2] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 12.590908][ C2] ? simple_recursive_removal (./include/linux/dcache.h:345 fs/libfs.c:610) 
[ 12.590912][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 12.590916][ 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) 
[ 12.590921][ C2] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:616) 
[ 12.590924][ C2] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 12.590929][ 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) 
[ 12.590934][ C2] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 12.590937][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 12.590942][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 12.590946][ 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) 
[ 12.590950][ C2] ? rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2570) 
[ 12.590955][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 12.590958][ C2] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 12.590962][ C2] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[ 12.590965][ C2] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 12.590969][ C2] ? pv_native_safe_halt (arch/x86/kernel/paravirt.c:81) 
[ 12.590972][ C2] ? default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:748) 
[ 12.590974][ C2] ? default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 12.590976][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 12.590979][ C2] ? do_idle (kernel/sched/idle.c:325) 
[ 12.590981][ C2] ? cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 12.590983][ C2] ? start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 12.590987][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:419) 
[ 12.590993][ C2] __put_net (net/core/net_namespace.c:732) 
[ 12.590996][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2366) 
[ 12.591000][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 12.591003][ C2] rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2570) 
[ 12.591007][ C2] ? find_held_lock (kernel/locking/lockdep.c:5348) 
[ 12.591012][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 12.591016][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 12.591020][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 12.591024][ C2] ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/preempt.h:104 ./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 12.591028][ C2] rcu_core (kernel/rcu/tree.c:2826) 
[ 12.591032][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 12.591037][ C2] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 12.591040][ C2] irq_exit_rcu (kernel/softirq.c:698) 
[ 12.591042][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[   12.591046][    C2]  </IRQ>
[   12.591047][    C2]  <TASK>
[ 12.591048][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 12.591051][ C2] RIP: 0010:pv_native_safe_halt (arch/x86/kernel/paravirt.c:81) 
[ 12.591055][ 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
[   12.591057][    C2] RSP: 0018:ffffc90000147de8 EFLAGS: 00000246
[   12.591061][    C2] RAX: 00000000000311dd RBX: 1ffff92000028fc1 RCX: ffffffff8f96ea19
[   12.591063][    C2] RDX: 0000000000000000 RSI: ffffffff90489a45 RDI: ffffffff8fc513a0
[   12.591065][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c2667a
[   12.591067][    C2] R10: ffff8880361333d3 R11: 0000000000000000 R12: 0000000000000000
[   12.591068][    C2] R13: ffff888001bf2340 R14: dffffc0000000000 R15: 0000000000000000
[ 12.591072][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:146) 
[ 12.591078][ C2] default_idle (./arch/x86/include/asm/paravirt.h:107 arch/x86/kernel/process.c:748) 
[ 12.591080][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 12.591082][ C2] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 12.591085][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 12.591089][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) 
[ 12.591093][ C2] do_idle (kernel/sched/idle.c:325) 
[ 12.591096][ C2] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 12.591099][ C2] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 12.591102][ 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