======================================
| [   13.965276][    C2] 1 lock held by ksoftirqd/2/27:
| [ 13.965459][ C2] #0: ffffffff98174480 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2562) 
| [   13.965799][    C2]
| [   13.965799][    C2] stack backtrace:
[   13.966034][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.966036][    C2] Call Trace:
[   13.966038][    C2]  <TASK>
[ 13.966041][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.966047][ C2] print_usage_bug.part.0 (kernel/locking/lockdep.c:4046) 
[ 13.966051][ C2] mark_lock_irq (kernel/locking/lockdep.c:4011 kernel/locking/lockdep.c:4057 kernel/locking/lockdep.c:4268) 
[ 13.966056][ C2] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 13.966060][ C2] ? save_trace (kernel/locking/lockdep.c:594) 
[ 13.966065][ C2] mark_lock (kernel/locking/lockdep.c:4754) 
[ 13.966068][ C2] mark_usage (kernel/locking/lockdep.c:4643) 
[ 13.966071][ C2] __lock_acquire (kernel/locking/lockdep.c:5189) 
[ 13.966075][ C2] lock_acquire.part.0 (kernel/locking/lockdep.c:472 kernel/locking/lockdep.c:5868) 
[ 13.966078][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.966081][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.966084][ C2] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5829) 
[ 13.966087][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.966090][ C2] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 13.966093][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.966095][ C2] simple_pin_fs (fs/libfs.c:1066) 
[ 13.966098][ C2] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 13.966102][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 13.966108][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 13.966111][ 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:2333) 
[ 13.966116][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.966120][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 13.966123][ C2] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.966128][ C2] ? kthread (kernel/kthread.c:464) 
[ 13.966132][ C2] ? ret_from_fork (arch/x86/kernel/process.c:153) 
[ 13.966134][ C2] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 13.966138][ C2] ? migrate_enable (./arch/x86/include/asm/preempt.h:104 ./include/linux/preempt.h:481 ./include/linux/preempt.h:481 kernel/sched/core.c:2417) 
[ 13.966141][ C2] ? __pfx_migrate_enable (kernel/sched/core.c:2392) 
[ 13.966145][ C2] __put_net (net/core/net_namespace.c:732) 
[ 13.966149][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2333) 
[ 13.966152][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.966156][ C2] rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.966161][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 13.966165][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.966168][ C2] ? note_gp_changes (kernel/rcu/tree.c:1324 (discriminator 1)) 
[ 13.966171][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 13.966176][ C2] rcu_core (kernel/rcu/tree.c:2826) 
[ 13.966180][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 13.966184][ C2] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 13.966187][ C2] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 13.966190][ C2] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.966193][ C2] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 13.966197][ C2] kthread (kernel/kthread.c:464) 
[ 13.966200][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.966203][ C2] ? ret_from_fork (arch/x86/kernel/process.c:152) 
[ 13.966205][ C2] ? __lock_release (kernel/locking/lockdep.c:5534) 
[ 13.966208][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.966211][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.966215][ C2] ret_from_fork (arch/x86/kernel/process.c:153) 
[ 13.966217][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.966220][ C2] ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
| [   13.978176][    C2] RCU nest depth: 0, expected: 0
| [   13.978377][    C2] INFO: lockdep is turned off.
| [   13.978573][    C2] Preemption disabled at:
| [ 13.978575][ C2] handle_softirqs (kernel/softirq.c:553) 
[   13.978971][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.978973][    C2] Call Trace:
[   13.978975][    C2]  <TASK>
[ 13.978977][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.978984][ C2] __might_resched (kernel/sched/core.c:8819) 
[ 13.978990][ C2] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 13.978994][ C2] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 13.978996][ C2] ? simple_recursive_removal (./include/linux/dcache.h:345 fs/libfs.c:610) 
[ 13.979001][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.979005][ 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) 
[ 13.979010][ C2] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:616) 
[ 13.979013][ C2] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 13.979018][ 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) 
[ 13.979023][ C2] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 13.979026][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 13.979032][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 13.979035][ 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:2333) 
[ 13.979040][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.979044][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 13.979047][ C2] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.979052][ C2] ? kthread (kernel/kthread.c:464) 
[ 13.979056][ C2] ? ret_from_fork (arch/x86/kernel/process.c:153) 
[ 13.979060][ C2] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 13.979065][ C2] ? migrate_enable (./arch/x86/include/asm/preempt.h:104 ./include/linux/preempt.h:481 ./include/linux/preempt.h:481 kernel/sched/core.c:2417) 
[ 13.979068][ C2] ? __pfx_migrate_enable (kernel/sched/core.c:2392) 
[ 13.979073][ C2] __put_net (net/core/net_namespace.c:732) 
[ 13.979076][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2333) 
[ 13.979080][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.979083][ C2] rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.979089][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 13.979093][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.979095][ C2] ? note_gp_changes (kernel/rcu/tree.c:1324 (discriminator 1)) 
[ 13.979099][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 13.979104][ C2] rcu_core (kernel/rcu/tree.c:2826) 
[ 13.979108][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 13.979112][ C2] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 13.979115][ C2] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 13.979118][ C2] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.979121][ C2] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 13.979125][ C2] kthread (kernel/kthread.c:464) 
[ 13.979129][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.979132][ C2] ? ret_from_fork (arch/x86/kernel/process.c:152) 
[ 13.979134][ C2] ? __lock_release (kernel/locking/lockdep.c:5534) 
[ 13.979137][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.979140][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.979144][ C2] ret_from_fork (arch/x86/kernel/process.c:153) 
[ 13.979146][ C2] ? __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