======================================
| [ 3948.341063][    C3] 1 lock held by ksoftirqd/3/32:
| [ 3948.341247][ C3] #0: ffffffff8b98b540 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2570) 
| [ 3948.341565][    C3]
| [ 3948.341565][    C3] stack backtrace:
[ 3948.341801][    C3] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 3948.341806][    C3] Call Trace:
[ 3948.341810][    C3]  <TASK>
[ 3948.341812][ C3] dump_stack_lvl (lib/dump_stack.c:123) 
[ 3948.341820][ C3] print_usage_bug.part.0 (kernel/locking/lockdep.c:4048) 
[ 3948.341825][ C3] mark_lock_irq (kernel/locking/lockdep.c:4013 kernel/locking/lockdep.c:4059 kernel/locking/lockdep.c:4270) 
[ 3948.341829][ C3] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 3948.341834][ C3] ? save_trace (kernel/locking/lockdep.c:595) 
[ 3948.341842][ C3] mark_lock (kernel/locking/lockdep.c:4756) 
[ 3948.341845][ C3] mark_usage (kernel/locking/lockdep.c:4645) 
[ 3948.341848][ C3] __lock_acquire (kernel/locking/lockdep.c:5194) 
[ 3948.341853][ C3] lock_acquire.part.0 (kernel/locking/lockdep.c:473 kernel/locking/lockdep.c:5873) 
[ 3948.341856][ C3] ? simple_pin_fs (fs/libfs.c:1067) 
[ 3948.341859][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 3948.341863][ C3] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5834) 
[ 3948.341865][ C3] ? simple_pin_fs (fs/libfs.c:1067) 
[ 3948.341869][ C3] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 3948.341872][ C3] ? simple_pin_fs (fs/libfs.c:1067) 
[ 3948.341875][ C3] simple_pin_fs (fs/libfs.c:1067) 
[ 3948.341878][ C3] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 3948.341881][ C3] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 3948.341892][ C3] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 3948.341895][ 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) 
[ 3948.341906][ C3] ? rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2578) 
[ 3948.341910][ C3] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 3948.341913][ C3] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 3948.341919][ C3] ? kthread (kernel/kthread.c:464) 
[ 3948.341923][ C3] ? ret_from_fork (arch/x86/kernel/process.c:148) 
[ 3948.341926][ C3] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 3948.341929][ C3] ? migrate_enable (./arch/x86/include/asm/preempt.h:104 ./include/linux/preempt.h:481 ./include/linux/preempt.h:481 kernel/sched/core.c:2427) 
[ 3948.341934][ C3] ? __pfx_migrate_enable (kernel/sched/core.c:2402) 
[ 3948.341940][ C3] __put_net (net/core/net_namespace.c:732) 
[ 3948.341947][ C3] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 3948.341951][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 3948.341954][ C3] rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2578) 
[ 3948.341960][ C3] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 3948.341964][ C3] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 3948.341967][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 3948.341969][ C3] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 3948.341974][ C3] rcu_core (kernel/rcu/tree.c:2834) 
[ 3948.341980][ C3] handle_softirqs (kernel/softirq.c:580) 
[ 3948.341985][ C3] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 3948.341988][ C3] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 3948.341990][ C3] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 3948.341994][ C3] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 3948.341998][ C3] kthread (kernel/kthread.c:464) 
[ 3948.342002][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 3948.342005][ C3] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 3948.342007][ C3] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 3948.342010][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 3948.342013][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 3948.342017][ C3] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 3948.342019][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 3948.342023][ C3] ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
| [ 3948.352778][    C3] RCU nest depth: 0, expected: 0
| [ 3948.352952][    C3] INFO: lockdep is turned off.
| [ 3948.353122][    C3] Preemption disabled at:
| [ 3948.353123][ C3] handle_softirqs (kernel/softirq.c:553) 
[ 3948.353462][    C3] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 3948.353463][    C3] Call Trace:
[ 3948.353465][    C3]  <TASK>
[ 3948.353467][ C3] dump_stack_lvl (lib/dump_stack.c:123) 
[ 3948.353475][ C3] __might_resched (kernel/sched/core.c:8796) 
[ 3948.353483][ C3] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 3948.353487][ C3] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 3948.353489][ C3] ? simple_recursive_removal (fs/libfs.c:614) 
[ 3948.353495][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 3948.353499][ 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) 
[ 3948.353506][ C3] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:617) 
[ 3948.353509][ 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) 
[ 3948.353513][ C3] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 3948.353519][ C3] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 3948.353522][ C3] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 3948.353527][ C3] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 3948.353530][ 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) 
[ 3948.353534][ C3] ? rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2578) 
[ 3948.353538][ C3] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 3948.353541][ C3] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 3948.353545][ C3] ? kthread (kernel/kthread.c:464) 
[ 3948.353549][ C3] ? ret_from_fork (arch/x86/kernel/process.c:148) 
[ 3948.353552][ C3] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 3948.353556][ C3] ? migrate_enable (./arch/x86/include/asm/preempt.h:104 ./include/linux/preempt.h:481 ./include/linux/preempt.h:481 kernel/sched/core.c:2427) 
[ 3948.353559][ C3] ? __pfx_migrate_enable (kernel/sched/core.c:2402) 
[ 3948.353565][ C3] __put_net (net/core/net_namespace.c:732) 
[ 3948.353569][ C3] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 3948.353573][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 3948.353576][ C3] rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2578) 
[ 3948.353582][ C3] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 3948.353586][ C3] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 3948.353590][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 3948.353593][ C3] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 3948.353598][ C3] rcu_core (kernel/rcu/tree.c:2834) 
[ 3948.353602][ C3] handle_softirqs (kernel/softirq.c:580) 
[ 3948.353606][ C3] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 3948.353610][ C3] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 3948.353612][ C3] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 3948.353615][ C3] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 3948.353619][ C3] kthread (kernel/kthread.c:464) 
[ 3948.353623][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 3948.353626][ C3] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 3948.353628][ C3] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 3948.353631][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 3948.353634][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 3948.353638][ C3] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 3948.353641][ 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