======================================
| [   15.756410][    C1] 1 lock held by ksoftirqd/1/22:
| [ 15.756621][ C1] #0: ffffffff97b774c0 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2570) 
| [   15.757057][    C1]
| [   15.757057][    C1] stack backtrace:
[   15.757356][    C1] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   15.757359][    C1] Call Trace:
[   15.757362][    C1]  <TASK>
[ 15.757366][ C1] dump_stack_lvl (lib/dump_stack.c:123) 
[ 15.757378][ C1] print_usage_bug.part.0 (kernel/locking/lockdep.c:4048) 
[ 15.757387][ C1] mark_lock_irq (kernel/locking/lockdep.c:4013 kernel/locking/lockdep.c:4059 kernel/locking/lockdep.c:4270) 
[ 15.757395][ C1] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 15.757404][ C1] ? save_trace (kernel/locking/lockdep.c:595) 
[ 15.757411][ C1] mark_lock (kernel/locking/lockdep.c:4756) 
[ 15.757418][ C1] mark_usage (kernel/locking/lockdep.c:4645) 
[ 15.757424][ C1] __lock_acquire (kernel/locking/lockdep.c:5194) 
[ 15.757430][ C1] ? __lock_acquire (kernel/locking/lockdep.c:5240) 
[ 15.757437][ C1] lock_acquire.part.0 (kernel/locking/lockdep.c:473 kernel/locking/lockdep.c:5873) 
[ 15.757442][ C1] ? simple_pin_fs (fs/libfs.c:1067) 
[ 15.757449][ C1] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 15.757457][ C1] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5834) 
[ 15.757460][ C1] ? simple_pin_fs (fs/libfs.c:1067) 
[ 15.757463][ C1] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 15.757467][ C1] ? simple_pin_fs (fs/libfs.c:1067) 
[ 15.757470][ C1] simple_pin_fs (fs/libfs.c:1067) 
[ 15.757473][ C1] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 15.757477][ C1] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 15.757483][ C1] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 15.757486][ C1] ? __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) 
[ 15.757493][ C1] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 15.757496][ C1] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 15.757499][ C1] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 15.757503][ C1] ? kthread (kernel/kthread.c:464) 
[ 15.757508][ C1] ? ret_from_fork (arch/x86/kernel/process.c:148) 
[ 15.757512][ C1] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 15.757515][ C1] ? migrate_enable (./arch/x86/include/asm/preempt.h:104 ./include/linux/preempt.h:481 ./include/linux/preempt.h:481 kernel/sched/core.c:2427) 
[ 15.757521][ C1] ? __pfx_migrate_enable (kernel/sched/core.c:2402) 
[ 15.757527][ C1] __put_net (net/core/net_namespace.c:732) 
[ 15.757532][ C1] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 15.757536][ C1] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 15.757539][ C1] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 15.757542][ C1] ? __schedule (kernel/sched/core.c:6658) 
[ 15.757549][ C1] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 15.757553][ C1] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 15.757556][ C1] ? note_gp_changes (kernel/rcu/tree.c:1326 (discriminator 1)) 
[ 15.757560][ C1] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 15.757566][ C1] rcu_core (kernel/rcu/tree.c:2834) 
[ 15.757571][ C1] handle_softirqs (kernel/softirq.c:579) 
[ 15.757577][ C1] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 15.757581][ C1] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 15.757584][ C1] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 15.757587][ C1] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 15.757590][ C1] kthread (kernel/kthread.c:464) 
[ 15.757593][ C1] ? __pfx_kthread (kernel/kthread.c:413) 
[ 15.757595][ C1] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 15.757598][ C1] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 15.757602][ C1] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 15.757605][ C1] ? __pfx_kthread (kernel/kthread.c:413) 
[ 15.757608][ C1] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 15.757612][ C1] ? __pfx_kthread (kernel/kthread.c:413) 
[ 15.757614][ C1] ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
| [   15.771439][    C1] RCU nest depth: 0, expected: 0
| [   15.771622][    C1] INFO: lockdep is turned off.
| [   15.771855][    C1] Preemption disabled at:
| [ 15.771857][ C1] handle_softirqs (kernel/softirq.c:553) 
[   15.772280][    C1] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   15.772283][    C1] Call Trace:
[   15.772285][    C1]  <TASK>
[ 15.772288][ C1] dump_stack_lvl (lib/dump_stack.c:123) 
[ 15.772295][ C1] __might_resched (kernel/sched/core.c:8796) 
[ 15.772304][ C1] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 15.772308][ C1] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 15.772311][ C1] ? simple_recursive_removal (fs/libfs.c:614) 
[ 15.772316][ C1] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 15.772322][ C1] ? 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) 
[ 15.772326][ C1] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:617) 
[ 15.772329][ C1] ? 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) 
[ 15.772331][ C1] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 15.772338][ C1] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 15.772342][ C1] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 15.772349][ C1] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 15.772353][ C1] ? __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) 
[ 15.772359][ C1] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 15.772365][ C1] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 15.772370][ C1] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 15.772375][ C1] ? kthread (kernel/kthread.c:464) 
[ 15.772380][ C1] ? ret_from_fork (arch/x86/kernel/process.c:148) 
[ 15.772386][ C1] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 15.772391][ C1] ? migrate_enable (./arch/x86/include/asm/preempt.h:104 ./include/linux/preempt.h:481 ./include/linux/preempt.h:481 kernel/sched/core.c:2427) 
[ 15.772397][ C1] ? __pfx_migrate_enable (kernel/sched/core.c:2402) 
[ 15.772408][ C1] __put_net (net/core/net_namespace.c:732) 
[ 15.772414][ C1] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 15.772420][ C1] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 15.772425][ C1] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 15.772431][ C1] ? __schedule (kernel/sched/core.c:6658) 
[ 15.772439][ C1] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 15.772444][ C1] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 15.772448][ C1] ? note_gp_changes (kernel/rcu/tree.c:1326 (discriminator 1)) 
[ 15.772451][ C1] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 15.772457][ C1] rcu_core (kernel/rcu/tree.c:2834) 
[ 15.772461][ C1] handle_softirqs (kernel/softirq.c:579) 
[ 15.772467][ C1] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 15.772471][ C1] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 15.772474][ C1] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 15.772477][ C1] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 15.772480][ C1] kthread (kernel/kthread.c:464) 
[ 15.772484][ C1] ? __pfx_kthread (kernel/kthread.c:413) 
[ 15.772486][ C1] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 15.772489][ C1] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 15.772493][ C1] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 15.772497][ C1] ? __pfx_kthread (kernel/kthread.c:413) 
[ 15.772500][ C1] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 15.772503][ C1] ? __pfx_kthread (kernel/kthread.c:413) 


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