======================================
| [   13.386878][    C3] 1 lock held by ksoftirqd/3/32:
| [ 13.387077][ C3] #0: ffffffff87f74480 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2562) 
| [   13.387417][    C3]
| [   13.387417][    C3] stack backtrace:
[   13.387660][    C3] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.387663][    C3] Call Trace:
[   13.387665][    C3]  <TASK>
[ 13.387668][ C3] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.387675][ C3] print_usage_bug.part.0 (kernel/locking/lockdep.c:4046) 
[ 13.387680][ C3] mark_lock_irq (kernel/locking/lockdep.c:4011 kernel/locking/lockdep.c:4057 kernel/locking/lockdep.c:4268) 
[ 13.387684][ C3] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 13.387689][ C3] ? save_trace (kernel/locking/lockdep.c:594) 
[ 13.387695][ C3] mark_lock (kernel/locking/lockdep.c:4754) 
[ 13.387699][ C3] mark_usage (kernel/locking/lockdep.c:4643) 
[ 13.387702][ C3] __lock_acquire (kernel/locking/lockdep.c:5189) 
[ 13.387706][ C3] lock_acquire.part.0 (kernel/locking/lockdep.c:472 kernel/locking/lockdep.c:5868) 
[ 13.387709][ C3] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.387713][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.387716][ C3] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5829) 
[ 13.387719][ C3] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.387722][ C3] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 13.387726][ C3] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.387728][ C3] simple_pin_fs (fs/libfs.c:1066) 
[ 13.387731][ C3] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 13.387735][ C3] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 13.387742][ C3] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 13.387745][ 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:2333) 
[ 13.387751][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.387755][ C3] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 13.387758][ C3] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.387764][ C3] ? kthread (kernel/kthread.c:464) 
[ 13.387769][ C3] ? ret_from_fork (arch/x86/kernel/process.c:153) 
[ 13.387772][ C3] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 13.387775][ C3] ? migrate_enable (./arch/x86/include/asm/preempt.h:104 ./include/linux/preempt.h:481 ./include/linux/preempt.h:481 kernel/sched/core.c:2417) 
[ 13.387779][ C3] ? __pfx_migrate_enable (kernel/sched/core.c:2392) 
[ 13.387783][ C3] __put_net (net/core/net_namespace.c:732) 
[ 13.387788][ C3] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2333) 
[ 13.387792][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.387795][ C3] rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.387800][ C3] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 13.387804][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.387807][ C3] ? note_gp_changes (kernel/rcu/tree.c:1324 (discriminator 1)) 
[ 13.387810][ C3] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 13.387817][ C3] rcu_core (kernel/rcu/tree.c:2826) 
[ 13.387821][ C3] handle_softirqs (kernel/softirq.c:579) 
[ 13.387825][ C3] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 13.387828][ C3] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 13.387831][ C3] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.387835][ C3] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 13.387839][ C3] kthread (kernel/kthread.c:464) 
[ 13.387842][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.387845][ C3] ? ret_from_fork (arch/x86/kernel/process.c:152) 
[ 13.387848][ C3] ? __lock_release (kernel/locking/lockdep.c:5534) 
[ 13.387851][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.387853][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.387857][ C3] ret_from_fork (arch/x86/kernel/process.c:153) 
[ 13.387859][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.387863][ C3] ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
| [   13.399498][    C3] RCU nest depth: 0, expected: 0
| [   13.399698][    C3] INFO: lockdep is turned off.
| [   13.399884][    C3] Preemption disabled at:
| [ 13.399886][ C3] handle_softirqs (kernel/softirq.c:553) 
[   13.400254][    C3] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.400257][    C3] Call Trace:
[   13.400259][    C3]  <TASK>
[ 13.400261][ C3] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.400268][ C3] __might_resched (kernel/sched/core.c:8819) 
[ 13.400276][ C3] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 13.400279][ C3] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 13.400282][ C3] ? simple_recursive_removal (./include/linux/dcache.h:345 fs/libfs.c:610) 
[ 13.400286][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.400291][ 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) 
[ 13.400296][ C3] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:616) 
[ 13.400299][ C3] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 13.400305][ 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) 
[ 13.400309][ C3] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 13.400313][ C3] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 13.400318][ C3] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 13.400322][ 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:2333) 
[ 13.400327][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.400331][ C3] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 13.400334][ C3] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.400338][ C3] ? kthread (kernel/kthread.c:464) 
[ 13.400342][ C3] ? ret_from_fork (arch/x86/kernel/process.c:153) 
[ 13.400346][ C3] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 13.400351][ C3] ? migrate_enable (./arch/x86/include/asm/preempt.h:104 ./include/linux/preempt.h:481 ./include/linux/preempt.h:481 kernel/sched/core.c:2417) 
[ 13.400354][ C3] ? __pfx_migrate_enable (kernel/sched/core.c:2392) 
[ 13.400359][ C3] __put_net (net/core/net_namespace.c:732) 
[ 13.400363][ C3] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2333) 
[ 13.400367][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.400370][ C3] rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.400376][ C3] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 13.400380][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.400382][ C3] ? note_gp_changes (kernel/rcu/tree.c:1324 (discriminator 1)) 
[ 13.400386][ C3] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 13.400392][ C3] rcu_core (kernel/rcu/tree.c:2826) 
[ 13.400395][ C3] handle_softirqs (kernel/softirq.c:579) 
[ 13.400399][ C3] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 13.400402][ C3] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 13.400411][ C3] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.400415][ C3] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 13.400419][ C3] kthread (kernel/kthread.c:464) 
[ 13.400422][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.400426][ C3] ? ret_from_fork (arch/x86/kernel/process.c:152) 
[ 13.400428][ C3] ? __lock_release (kernel/locking/lockdep.c:5534) 
[ 13.400431][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.400434][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.400438][ C3] ret_from_fork (arch/x86/kernel/process.c:153) 
[ 13.400441][ C3] ? __pfx_kthread (kernel/kthread.c:413) 


Finger prints:
mark_lock_irq:mark_lock:mark_usage:__lock_acquire:_raw_spin_lock
handle_softirqs:dump_stack_lvl:__might_resched:down_write:simple_recursive_removal