======================================
| [   12.845504][    C2] 1 lock held by ksoftirqd/2/27:
| [ 12.845683][ C2] #0: ffffffffaa974480 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2562) 
| [   12.846002][    C2]
| [   12.846002][    C2] stack backtrace:
[   12.846227][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   12.846229][    C2] Call Trace:
[   12.846231][    C2]  <TASK>
[ 12.846234][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 12.846242][ C2] print_usage_bug.part.0 (kernel/locking/lockdep.c:4046) 
[ 12.846246][ C2] mark_lock_irq (kernel/locking/lockdep.c:4011 kernel/locking/lockdep.c:4057 kernel/locking/lockdep.c:4268) 
[ 12.846250][ C2] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 12.846255][ C2] ? save_trace (kernel/locking/lockdep.c:594) 
[ 12.846262][ C2] mark_lock (kernel/locking/lockdep.c:4754) 
[ 12.846265][ C2] mark_usage (kernel/locking/lockdep.c:4643) 
[ 12.846268][ C2] __lock_acquire (kernel/locking/lockdep.c:5189) 
[ 12.846272][ C2] lock_acquire.part.0 (kernel/locking/lockdep.c:472 kernel/locking/lockdep.c:5868) 
[ 12.846275][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 12.846278][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 12.846282][ C2] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5829) 
[ 12.846284][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 12.846288][ C2] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 12.846291][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 12.846293][ C2] simple_pin_fs (fs/libfs.c:1066) 
[ 12.846296][ C2] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 12.846299][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 12.846307][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 12.846310][ 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) 
[ 12.846317][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 12.846321][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 12.846324][ C2] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 12.846330][ C2] ? kthread (kernel/kthread.c:464) 
[ 12.846335][ C2] ? ret_from_fork (arch/x86/kernel/process.c:153) 
[ 12.846338][ C2] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 12.846341][ 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) 
[ 12.846345][ C2] ? __pfx_migrate_enable (kernel/sched/core.c:2392) 
[ 12.846349][ C2] __put_net (net/core/net_namespace.c:732) 
[ 12.846354][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2333) 
[ 12.846357][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 12.846360][ C2] rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 12.846366][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 12.846370][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 12.846372][ C2] ? note_gp_changes (kernel/rcu/tree.c:1324 (discriminator 1)) 
[ 12.846376][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 12.846382][ C2] rcu_core (kernel/rcu/tree.c:2826) 
[ 12.846386][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 12.846390][ C2] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 12.846393][ C2] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 12.846396][ C2] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 12.846399][ C2] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 12.846403][ C2] kthread (kernel/kthread.c:464) 
[ 12.846407][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 12.846410][ C2] ? ret_from_fork (arch/x86/kernel/process.c:152) 
[ 12.846412][ C2] ? __lock_release (kernel/locking/lockdep.c:5534) 
[ 12.846415][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 12.846418][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 12.846421][ C2] ret_from_fork (arch/x86/kernel/process.c:153) 
[ 12.846424][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 12.846427][ C2] ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
| [   12.857193][    C2] RCU nest depth: 0, expected: 0
| [   12.857380][    C2] INFO: lockdep is turned off.
| [   12.857559][    C2] Preemption disabled at:
| [ 12.857561][ C2] handle_softirqs (kernel/softirq.c:553) 
[   12.857934][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   12.857935][    C2] Call Trace:
[   12.857937][    C2]  <TASK>
[ 12.857939][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 12.857945][ C2] __might_resched (kernel/sched/core.c:8819) 
[ 12.857952][ C2] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 12.857956][ C2] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 12.857958][ C2] ? simple_recursive_removal (./include/linux/dcache.h:345 fs/libfs.c:610) 
[ 12.857963][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 12.857967][ 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) 
[ 12.857971][ C2] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:616) 
[ 12.857974][ C2] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 12.857979][ 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) 
[ 12.857983][ C2] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 12.857987][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 12.857991][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 12.857995][ 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) 
[ 12.857999][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 12.858003][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 12.858006][ C2] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 12.858010][ C2] ? kthread (kernel/kthread.c:464) 
[ 12.858014][ C2] ? ret_from_fork (arch/x86/kernel/process.c:153) 
[ 12.858017][ C2] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 12.858021][ 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) 
[ 12.858025][ C2] ? __pfx_migrate_enable (kernel/sched/core.c:2392) 
[ 12.858030][ C2] __put_net (net/core/net_namespace.c:732) 
[ 12.858032][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2333) 
[ 12.858036][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 12.858039][ C2] rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 12.858044][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 12.858049][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 12.858051][ C2] ? note_gp_changes (kernel/rcu/tree.c:1324 (discriminator 1)) 
[ 12.858055][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 12.858059][ C2] rcu_core (kernel/rcu/tree.c:2826) 
[ 12.858063][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 12.858067][ C2] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 12.858070][ C2] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 12.858073][ C2] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 12.858076][ C2] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 12.858080][ C2] kthread (kernel/kthread.c:464) 
[ 12.858084][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 12.858087][ C2] ? ret_from_fork (arch/x86/kernel/process.c:152) 
[ 12.858089][ C2] ? __lock_release (kernel/locking/lockdep.c:5534) 
[ 12.858092][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 12.858095][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 12.858099][ C2] ret_from_fork (arch/x86/kernel/process.c:153) 
[ 12.858101][ 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