======================================
| [ 13.901677][ C3] #2: ffffffff99ff76d0 (cgroup_threadgroup_rwsem){.+.+}-{0:0}, at: cgroup_can_fork (kernel/cgroup/cgroup.c:6671) 
| [ 13.902106][ C3] #3: ffffffff99f774c0 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2570) 
| [   13.902674][    C3]
| [   13.902674][    C3] stack backtrace:
[   13.903072][    C3] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.903077][    C3] Workqueue: events_unbound call_usermodehelper_exec_work
[   13.903088][    C3] Call Trace:
[   13.903091][    C3]  <IRQ>
[ 13.903095][ C3] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.903106][ C3] print_usage_bug.part.0 (kernel/locking/lockdep.c:4048) 
[ 13.903116][ C3] mark_lock_irq (kernel/locking/lockdep.c:4013 kernel/locking/lockdep.c:4059 kernel/locking/lockdep.c:4270) 
[ 13.903124][ C3] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 13.903132][ C3] ? save_trace (kernel/locking/lockdep.c:595) 
[ 13.903140][ C3] mark_lock (kernel/locking/lockdep.c:4756) 
[ 13.903146][ C3] mark_usage (kernel/locking/lockdep.c:4645) 
[ 13.903152][ C3] __lock_acquire (kernel/locking/lockdep.c:5194) 
[ 13.903158][ C3] ? __lock_acquire (kernel/locking/lockdep.c:5240) 
[ 13.903165][ C3] lock_acquire.part.0 (kernel/locking/lockdep.c:473 kernel/locking/lockdep.c:5873) 
[ 13.903171][ C3] ? simple_pin_fs (fs/libfs.c:1067) 
[ 13.903178][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.903186][ C3] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5834) 
[ 13.903191][ C3] ? simple_pin_fs (fs/libfs.c:1067) 
[ 13.903198][ C3] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 13.903206][ C3] ? simple_pin_fs (fs/libfs.c:1067) 
[ 13.903210][ C3] simple_pin_fs (fs/libfs.c:1067) 
[ 13.903216][ C3] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 13.903223][ C3] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 13.903230][ C3] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 13.903235][ C3] ? __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) 
[ 13.903243][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.903248][ C3] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 13.903253][ C3] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 13.903260][ C3] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[ 13.903268][ C3] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.903274][ C3] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 13.903280][ C3] ? sched_cgroup_fork (kernel/sched/core.c:4826) 
[ 13.903286][ C3] ? copy_process (kernel/fork.c:2542) 
[ 13.903293][ C3] ? kernel_clone (./include/linux/random.h:26 kernel/fork.c:2860) 
[ 13.903297][ C3] ? user_mode_thread (kernel/fork.c:2928) 
[ 13.903303][ C3] ? call_usermodehelper_exec_work (kernel/umh.c:132 kernel/umh.c:163) 
[ 13.903308][ C3] ? process_one_work (kernel/workqueue.c:3238) 
[ 13.903314][ C3] ? worker_thread (kernel/workqueue.c:3315 kernel/workqueue.c:3402) 
[ 13.903324][ C3] __put_net (net/core/net_namespace.c:732) 
[ 13.903331][ C3] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 13.903337][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.903341][ C3] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.903348][ C3] ? find_held_lock (kernel/locking/lockdep.c:5353) 
[ 13.903354][ C3] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 13.903360][ C3] ? mark_held_locks (kernel/locking/lockdep.c:4328) 
[ 13.903365][ C3] ? note_gp_changes (kernel/rcu/tree.c:1326 (discriminator 1)) 
[ 13.903369][ C3] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 13.903377][ C3] rcu_core (kernel/rcu/tree.c:2834) 
[ 13.903385][ C3] handle_softirqs (kernel/softirq.c:579) 
[ 13.903394][ C3] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 13.903400][ C3] irq_exit_rcu (kernel/softirq.c:698) 
[ 13.903405][ C3] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[   13.903411][    C3]  </IRQ>
[   13.903413][    C3]  <TASK>
[ 13.903415][ C3] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.903420][ C3] RIP: 0010:_raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 13.903426][ C3] Code: 74 24 10 e8 c1 fe 81 fd 48 89 ef e8 79 51 82 fd 81 e3 00 02 00 00 75 29 9c 58 f6 c4 02 75 35 48 85 db 74 01 fb bf 01 00 00 00 <e8> fa 4e 76 fd 65 8b 05 13 bd 96 02 85 c0 74 0e 5b 5d c3 cc cc cc
All code
========
   0:	74 24                	je     0x26
   2:	10 e8                	adc    %ch,%al
   4:	c1 fe 81             	sar    $0x81,%esi
   7:	fd                   	std
   8:	48 89 ef             	mov    %rbp,%rdi
   b:	e8 79 51 82 fd       	call   0xfffffffffd825189
  10:	81 e3 00 02 00 00    	and    $0x200,%ebx
  16:	75 29                	jne    0x41
  18:	9c                   	pushf
  19:	58                   	pop    %rax
  1a:	f6 c4 02             	test   $0x2,%ah
  1d:	75 35                	jne    0x54
  1f:	48 85 db             	test   %rbx,%rbx
  22:	74 01                	je     0x25
  24:	fb                   	sti
  25:	bf 01 00 00 00       	mov    $0x1,%edi
  2a:*	e8 fa 4e 76 fd       	call   0xfffffffffd764f29		<-- trapping instruction
  2f:	65 8b 05 13 bd 96 02 	mov    %gs:0x296bd13(%rip),%eax        # 0x296bd49
  36:	85 c0                	test   %eax,%eax
  38:	74 0e                	je     0x48
  3a:	5b                   	pop    %rbx
  3b:	5d                   	pop    %rbp
  3c:	c3                   	ret
  3d:	cc                   	int3
  3e:	cc                   	int3
  3f:	cc                   	int3

Code starting with the faulting instruction
===========================================
   0:	e8 fa 4e 76 fd       	call   0xfffffffffd764eff
   5:	65 8b 05 13 bd 96 02 	mov    %gs:0x296bd13(%rip),%eax        # 0x296bd1f
   c:	85 c0                	test   %eax,%eax
   e:	74 0e                	je     0x1e
  10:	5b                   	pop    %rbx
  11:	5d                   	pop    %rbp
  12:	c3                   	ret
  13:	cc                   	int3
  14:	cc                   	int3
  15:	cc                   	int3
[   13.903431][    C3] RSP: 0018:ffffc900006b7870 EFLAGS: 00000206
[   13.903436][    C3] RAX: 0000000000000006 RBX: 0000000000000200 RCX: 0000000000000080
[   13.903439][    C3] RDX: 0000000000000000 RSI: ffffffff99a9175c RDI: 0000000000000001
[   13.903442][    C3] RBP: ffff888008e7ac68 R08: 0000000000000001 R09: 0000000000000001
[   13.903446][    C3] R10: ffffffff9a9e7cd7 R11: ffff888008e7ac80 R12: 0000000000000000
[   13.903449][    C3] R13: 0000000000000296 R14: ffff888008e7ac68 R15: 0000000000000003
[ 13.903461][ C3] sched_cgroup_fork (kernel/sched/core.c:4826) 
[ 13.903467][ C3] ? debug_mutex_init (kernel/locking/mutex-debug.c:90) 
[ 13.903474][ C3] copy_process (kernel/fork.c:2542) 
[ 13.903485][ C3] ? __pfx_copy_process (kernel/fork.c:2178) 
[ 13.903491][ C3] ? debug_object_deactivate (lib/debugobjects.c:889) 
[ 13.903499][ C3] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 13.903510][ C3] kernel_clone (./include/linux/random.h:26 kernel/fork.c:2860) 
[ 13.903517][ C3] ? __pfx_kernel_clone (kernel/fork.c:2819) 
[ 13.903522][ C3] ? rcu_read_lock_any_held (kernel/rcu/update.c:386 kernel/rcu/update.c:380) 
[ 13.903530][ C3] ? validate_chain (kernel/locking/lockdep.c:3804 kernel/locking/lockdep.c:3824 kernel/locking/lockdep.c:3879) 
[ 13.903539][ C3] ? __lock_acquire (kernel/locking/lockdep.c:5240) 
[ 13.903548][ C3] user_mode_thread (kernel/fork.c:2928) 
[ 13.903554][ C3] ? __pfx_user_mode_thread (kernel/fork.c:2928) 
[ 13.903565][ C3] ? __pfx_call_usermodehelper_exec_async (kernel/umh.c:64) 
[ 13.903571][ C3] ? __pfx_kernel_sigaction (kernel/signal.c:4276) 
[ 13.903578][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.903586][ C3] call_usermodehelper_exec_work (kernel/umh.c:132 kernel/umh.c:163) 
[ 13.903593][ C3] process_one_work (kernel/workqueue.c:3238) 
[ 13.903603][ C3] ? __pfx_process_one_work (kernel/workqueue.c:3140) 
[ 13.903612][ C3] ? assign_work (kernel/workqueue.c:1200) 
[ 13.903620][ C3] worker_thread (kernel/workqueue.c:3315 kernel/workqueue.c:3402) 
[ 13.903629][ C3] ? __pfx_worker_thread (kernel/workqueue.c:3348) 
[ 13.903634][ C3] kthread (kernel/kthread.c:464) 
[ 13.903640][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.903644][ C3] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 13.903651][ C3] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 13.903656][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.903661][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.903667][ C3] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 13.903672][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.903677][ C3] ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
| [   13.938696][    C3] RCU nest depth: 0, expected: 0
| [   13.938895][    C3] INFO: lockdep is turned off.
| [   13.939088][    C3] Preemption disabled at:
| [ 13.939090][ C3] 0x0 
[   13.939417][    C3] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.939419][    C3] Workqueue: events_unbound call_usermodehelper_exec_work
[   13.939431][    C3] Call Trace:
[   13.939434][    C3]  <IRQ>
[ 13.939437][ C3] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.939446][ C3] __might_resched (kernel/sched/core.c:8796) 
[ 13.939455][ C3] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 13.939459][ C3] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 13.939462][ C3] ? simple_recursive_removal (fs/libfs.c:614) 
[ 13.939468][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.939475][ C3] ? 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) 
[ 13.939479][ C3] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:617) 
[ 13.939483][ C3] ? 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) 
[ 13.939486][ C3] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 13.939492][ C3] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 13.939496][ C3] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 13.939502][ C3] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 13.939504][ C3] ? __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) 
[ 13.939511][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.939516][ C3] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 13.939518][ C3] ? irq_exit_rcu (kernel/softirq.c:698) 
[ 13.939524][ C3] ? sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[ 13.939530][ C3] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.939535][ C3] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 13.939540][ C3] ? sched_cgroup_fork (kernel/sched/core.c:4826) 
[ 13.939544][ C3] ? copy_process (kernel/fork.c:2542) 
[ 13.939549][ C3] ? kernel_clone (./include/linux/random.h:26 kernel/fork.c:2860) 
[ 13.939552][ C3] ? user_mode_thread (kernel/fork.c:2928) 
[ 13.939555][ C3] ? call_usermodehelper_exec_work (kernel/umh.c:132 kernel/umh.c:163) 
[ 13.939559][ C3] ? process_one_work (kernel/workqueue.c:3238) 
[ 13.939563][ C3] ? worker_thread (kernel/workqueue.c:3315 kernel/workqueue.c:3402) 
[ 13.939568][ C3] __put_net (net/core/net_namespace.c:732) 
[ 13.939573][ C3] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 13.939578][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.939581][ C3] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.939584][ C3] ? find_held_lock (kernel/locking/lockdep.c:5353) 
[ 13.939589][ C3] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 13.939592][ C3] ? mark_held_locks (kernel/locking/lockdep.c:4328) 
[ 13.939598][ C3] ? note_gp_changes (kernel/rcu/tree.c:1326 (discriminator 1)) 
[ 13.939601][ C3] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 13.939606][ C3] rcu_core (kernel/rcu/tree.c:2834) 
[ 13.939611][ C3] handle_softirqs (kernel/softirq.c:579) 
[ 13.939616][ C3] __irq_exit_rcu (kernel/softirq.c:614 kernel/softirq.c:453 kernel/softirq.c:680) 
[ 13.939620][ C3] irq_exit_rcu (kernel/softirq.c:698) 
[ 13.939623][ C3] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 arch/x86/kernel/apic/apic.c:1050) 
[   13.939626][    C3]  </IRQ>
[   13.939627][    C3]  <TASK>
[ 13.939629][ C3] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 13.939632][ C3] RIP: 0010:_raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 13.939636][ C3] Code: 74 24 10 e8 c1 fe 81 fd 48 89 ef e8 79 51 82 fd 81 e3 00 02 00 00 75 29 9c 58 f6 c4 02 75 35 48 85 db 74 01 fb bf 01 00 00 00 <e8> fa 4e 76 fd 65 8b 05 13 bd 96 02 85 c0 74 0e 5b 5d c3 cc cc cc
All code
========
   0:	74 24                	je     0x26
   2:	10 e8                	adc    %ch,%al
   4:	c1 fe 81             	sar    $0x81,%esi
   7:	fd                   	std
   8:	48 89 ef             	mov    %rbp,%rdi
   b:	e8 79 51 82 fd       	call   0xfffffffffd825189
  10:	81 e3 00 02 00 00    	and    $0x200,%ebx
  16:	75 29                	jne    0x41
  18:	9c                   	pushf
  19:	58                   	pop    %rax
  1a:	f6 c4 02             	test   $0x2,%ah
  1d:	75 35                	jne    0x54
  1f:	48 85 db             	test   %rbx,%rbx
  22:	74 01                	je     0x25
  24:	fb                   	sti
  25:	bf 01 00 00 00       	mov    $0x1,%edi
  2a:*	e8 fa 4e 76 fd       	call   0xfffffffffd764f29		<-- trapping instruction
  2f:	65 8b 05 13 bd 96 02 	mov    %gs:0x296bd13(%rip),%eax        # 0x296bd49
  36:	85 c0                	test   %eax,%eax
  38:	74 0e                	je     0x48
  3a:	5b                   	pop    %rbx
  3b:	5d                   	pop    %rbp
  3c:	c3                   	ret
  3d:	cc                   	int3
  3e:	cc                   	int3
  3f:	cc                   	int3

Code starting with the faulting instruction
===========================================
   0:	e8 fa 4e 76 fd       	call   0xfffffffffd764eff
   5:	65 8b 05 13 bd 96 02 	mov    %gs:0x296bd13(%rip),%eax        # 0x296bd1f
   c:	85 c0                	test   %eax,%eax
   e:	74 0e                	je     0x1e
  10:	5b                   	pop    %rbx
  11:	5d                   	pop    %rbp
  12:	c3                   	ret
  13:	cc                   	int3
  14:	cc                   	int3
  15:	cc                   	int3
[   13.939638][    C3] RSP: 0018:ffffc900006b7870 EFLAGS: 00000206
[   13.939642][    C3] RAX: 0000000000000006 RBX: 0000000000000200 RCX: 0000000000000080
[   13.939643][    C3] RDX: 0000000000000000 RSI: ffffffff99a9175c RDI: 0000000000000001
[   13.939645][    C3] RBP: ffff888008e7ac68 R08: 0000000000000001 R09: 0000000000000001
[   13.939647][    C3] R10: ffffffff9a9e7cd7 R11: ffff888008e7ac80 R12: 0000000000000000
[   13.939648][    C3] R13: 0000000000000296 R14: ffff888008e7ac68 R15: 0000000000000003
[ 13.939655][ C3] sched_cgroup_fork (kernel/sched/core.c:4826) 
[ 13.939658][ C3] ? debug_mutex_init (kernel/locking/mutex-debug.c:90) 
[ 13.939662][ C3] copy_process (kernel/fork.c:2542) 
[ 13.939677][ C3] ? __pfx_copy_process (kernel/fork.c:2178) 
[ 13.939681][ C3] ? debug_object_deactivate (lib/debugobjects.c:889) 
[ 13.939687][ C3] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 13.939693][ C3] kernel_clone (./include/linux/random.h:26 kernel/fork.c:2860) 
[ 13.939698][ C3] ? __pfx_kernel_clone (kernel/fork.c:2819) 
[ 13.939701][ C3] ? rcu_read_lock_any_held (kernel/rcu/update.c:386 kernel/rcu/update.c:380) 
[ 13.939707][ C3] ? validate_chain (kernel/locking/lockdep.c:3804 kernel/locking/lockdep.c:3824 kernel/locking/lockdep.c:3879) 
[ 13.939713][ C3] ? __lock_acquire (kernel/locking/lockdep.c:5240) 
[ 13.939718][ C3] user_mode_thread (kernel/fork.c:2928) 
[ 13.939722][ C3] ? __pfx_user_mode_thread (kernel/fork.c:2928) 
[ 13.939728][ C3] ? __pfx_call_usermodehelper_exec_async (kernel/umh.c:64) 
[ 13.939732][ C3] ? __pfx_kernel_sigaction (kernel/signal.c:4276) 
[ 13.939736][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.939741][ C3] call_usermodehelper_exec_work (kernel/umh.c:132 kernel/umh.c:163) 
[ 13.939745][ C3] process_one_work (kernel/workqueue.c:3238) 
[ 13.939751][ C3] ? __pfx_process_one_work (kernel/workqueue.c:3140) 
[ 13.939756][ C3] ? assign_work (kernel/workqueue.c:1200) 
[ 13.939760][ C3] worker_thread (kernel/workqueue.c:3315 kernel/workqueue.c:3402) 
[ 13.939766][ C3] ? __pfx_worker_thread (kernel/workqueue.c:3348) 
[ 13.939769][ C3] kthread (kernel/kthread.c:464) 
[ 13.939774][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.939776][ C3] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 13.939782][ C3] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 13.939786][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.939789][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.939792][ C3] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 13.939795][ C3] ? __pfx_kthread (kernel/kthread.c:413) 


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