======================================
| [   13.211169][    C2] 1 lock held by ksoftirqd/2/27:
| [ 13.211350][ C2] #0: ffffffff9d374480 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2562) 
| [   13.211652][    C2]
| [   13.211652][    C2] stack backtrace:
[   13.211865][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.211867][    C2] Call Trace:
[   13.211869][    C2]  <TASK>
[ 13.211871][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.211877][ C2] print_usage_bug.part.0 (kernel/locking/lockdep.c:4046) 
[ 13.211881][ C2] mark_lock_irq (kernel/locking/lockdep.c:4011 kernel/locking/lockdep.c:4057 kernel/locking/lockdep.c:4268) 
[ 13.211885][ C2] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 13.211889][ C2] ? save_trace (kernel/locking/lockdep.c:594) 
[ 13.211895][ C2] mark_lock (kernel/locking/lockdep.c:4754) 
[ 13.211898][ C2] mark_usage (kernel/locking/lockdep.c:4643) 
[ 13.211901][ C2] __lock_acquire (kernel/locking/lockdep.c:5189) 
[ 13.211905][ C2] lock_acquire.part.0 (kernel/locking/lockdep.c:472 kernel/locking/lockdep.c:5868) 
[ 13.211908][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.211911][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.211914][ C2] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5829) 
[ 13.211916][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.211920][ C2] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 13.211923][ C2] ? simple_pin_fs (fs/libfs.c:1066) 
[ 13.211925][ C2] simple_pin_fs (fs/libfs.c:1066) 
[ 13.211928][ C2] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 13.211931][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 13.211937][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 13.211940][ 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) 
[ 13.211945][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.211949][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 13.211952][ C2] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.211956][ C2] ? kthread (kernel/kthread.c:464) 
[ 13.211960][ C2] ? ret_from_fork (arch/x86/kernel/process.c:153) 
[ 13.211963][ C2] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 13.211966][ 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) 
[ 13.211969][ C2] ? __pfx_migrate_enable (kernel/sched/core.c:2392) 
[ 13.211974][ C2] __put_net (net/core/net_namespace.c:732) 
[ 13.211977][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2333) 
[ 13.211981][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.211984][ C2] rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.211989][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 13.211993][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.211996][ C2] ? note_gp_changes (kernel/rcu/tree.c:1324 (discriminator 1)) 
[ 13.211999][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 13.212005][ C2] rcu_core (kernel/rcu/tree.c:2826) 
[ 13.212009][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 13.212013][ C2] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 13.212016][ C2] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 13.212018][ C2] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.212022][ C2] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 13.212026][ C2] kthread (kernel/kthread.c:464) 
[ 13.212029][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.212032][ C2] ? ret_from_fork (arch/x86/kernel/process.c:152) 
[ 13.212034][ C2] ? __lock_release (kernel/locking/lockdep.c:5534) 
[ 13.212037][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.212040][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.212044][ C2] ret_from_fork (arch/x86/kernel/process.c:153) 
[ 13.212046][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.212050][ C2] ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
| [   13.221998][    C2] RCU nest depth: 0, expected: 0
| [   13.222162][    C2] INFO: lockdep is turned off.
| [   13.222322][    C2] Preemption disabled at:
| [ 13.222324][ C2] handle_softirqs (kernel/softirq.c:553) 
[   13.222661][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.222663][    C2] Call Trace:
[   13.222665][    C2]  <TASK>
[ 13.222667][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.222673][ C2] __might_resched (kernel/sched/core.c:8819) 
[ 13.222678][ C2] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 13.222681][ C2] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 13.222684][ C2] ? simple_recursive_removal (./include/linux/dcache.h:345 fs/libfs.c:610) 
[ 13.222687][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.222691][ 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) 
[ 13.222696][ C2] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:616) 
[ 13.222699][ C2] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 13.222702][ 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) 
[ 13.222707][ C2] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 13.222710][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:423 lib/ref_tracker.c:195) 
[ 13.222715][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 13.222718][ 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) 
[ 13.222722][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.222726][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 13.222729][ C2] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.222733][ C2] ? kthread (kernel/kthread.c:464) 
[ 13.222736][ C2] ? ret_from_fork (arch/x86/kernel/process.c:153) 
[ 13.222738][ C2] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 13.222742][ 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) 
[ 13.222745][ C2] ? __pfx_migrate_enable (kernel/sched/core.c:2392) 
[ 13.222750][ C2] __put_net (net/core/net_namespace.c:732) 
[ 13.222753][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2333) 
[ 13.222757][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.222760][ C2] rcu_do_batch (kernel/rcu/tree.c:2568) 
[ 13.222765][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2492) 
[ 13.222770][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.222772][ C2] ? note_gp_changes (kernel/rcu/tree.c:1324 (discriminator 1)) 
[ 13.222776][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473) 
[ 13.222781][ C2] rcu_core (kernel/rcu/tree.c:2826) 
[ 13.222784][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 13.222788][ C2] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 13.222791][ C2] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 13.222794][ C2] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.222797][ C2] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 13.222801][ C2] kthread (kernel/kthread.c:464) 
[ 13.222805][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.222808][ C2] ? ret_from_fork (arch/x86/kernel/process.c:152) 
[ 13.222810][ C2] ? __lock_release (kernel/locking/lockdep.c:5534) 
[ 13.222813][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:736) 
[ 13.222816][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.222819][ C2] ret_from_fork (arch/x86/kernel/process.c:153) 
[ 13.222822][ 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