======================================
| [ 4114.708563][    C2] 1 lock held by ksoftirqd/2/27:
| [ 4114.708757][ C2] #0: ffffffffa6b8b540 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2570) 
| [ 4114.709108][    C2]
| [ 4114.709108][    C2] stack backtrace:
[ 4114.709356][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 4114.709361][    C2] Call Trace:
[ 4114.709364][    C2]  <TASK>
[ 4114.709367][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 4114.709377][ C2] print_usage_bug.part.0 (kernel/locking/lockdep.c:4048) 
[ 4114.709381][ C2] mark_lock_irq (kernel/locking/lockdep.c:4013 kernel/locking/lockdep.c:4059 kernel/locking/lockdep.c:4270) 
[ 4114.709385][ C2] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 4114.709394][ C2] ? save_trace (kernel/locking/lockdep.c:595) 
[ 4114.709401][ C2] mark_lock (kernel/locking/lockdep.c:4756) 
[ 4114.709404][ C2] mark_usage (kernel/locking/lockdep.c:4645) 
[ 4114.709407][ C2] __lock_acquire (kernel/locking/lockdep.c:5194) 
[ 4114.709410][ C2] ? __lock_acquire (kernel/locking/lockdep.c:5240) 
[ 4114.709414][ C2] lock_acquire.part.0 (kernel/locking/lockdep.c:473 kernel/locking/lockdep.c:5873) 
[ 4114.709417][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 4114.709420][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 4114.709423][ C2] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5834) 
[ 4114.709426][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 4114.709431][ C2] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 4114.709434][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 4114.709436][ C2] simple_pin_fs (fs/libfs.c:1067) 
[ 4114.709440][ C2] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 4114.709443][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 4114.709455][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 4114.709458][ 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:2376) 
[ 4114.709470][ C2] ? rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2578) 
[ 4114.709474][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 4114.709476][ C2] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 4114.709485][ C2] ? kthread (kernel/kthread.c:464) 
[ 4114.709491][ C2] ? ret_from_fork (arch/x86/kernel/process.c:148) 
[ 4114.709493][ C2] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 4114.709496][ C2] ? migrate_enable (./arch/x86/include/asm/preempt.h:104 ./include/linux/preempt.h:481 ./include/linux/preempt.h:481 kernel/sched/core.c:2427) 
[ 4114.709503][ C2] ? __pfx_migrate_enable (kernel/sched/core.c:2402) 
[ 4114.709508][ C2] __put_net (net/core/net_namespace.c:732) 
[ 4114.709516][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 4114.709519][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 4114.709523][ C2] rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2578) 
[ 4114.709529][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 4114.709533][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 4114.709535][ C2] ? note_gp_changes (kernel/rcu/tree.c:1326 (discriminator 1)) 
[ 4114.709538][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 4114.709545][ C2] rcu_core (kernel/rcu/tree.c:2834) 
[ 4114.709552][ C2] handle_softirqs (kernel/softirq.c:580) 
[ 4114.709556][ C2] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 4114.709559][ C2] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 4114.709562][ C2] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 4114.709566][ C2] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 4114.709569][ C2] kthread (kernel/kthread.c:464) 
[ 4114.709573][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 4114.709576][ C2] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 4114.709578][ C2] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 4114.709581][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 4114.709584][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 4114.709588][ C2] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 4114.709590][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 4114.709594][ C2] ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
| [ 4114.721122][    C2] RCU nest depth: 0, expected: 0
| [ 4114.721319][    C2] INFO: lockdep is turned off.
| [ 4114.721728][    C2] Preemption disabled at:
| [ 4114.721730][ C2] handle_softirqs (kernel/softirq.c:553) 
[ 4114.722115][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 4114.722117][    C2] Call Trace:
[ 4114.722119][    C2]  <TASK>
[ 4114.722120][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 4114.722127][ C2] __might_resched (kernel/sched/core.c:8796) 
[ 4114.722136][ C2] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 4114.722140][ C2] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 4114.722143][ C2] ? simple_recursive_removal (fs/libfs.c:614) 
[ 4114.722147][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 4114.722151][ 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) 
[ 4114.722156][ C2] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:617) 
[ 4114.722159][ 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) 
[ 4114.722162][ C2] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 4114.722168][ C2] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 4114.722171][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 4114.722176][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 4114.722178][ 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:2376) 
[ 4114.722182][ C2] ? rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2578) 
[ 4114.722187][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 4114.722189][ C2] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 4114.722193][ C2] ? kthread (kernel/kthread.c:464) 
[ 4114.722197][ C2] ? ret_from_fork (arch/x86/kernel/process.c:148) 
[ 4114.722200][ C2] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 4114.722204][ C2] ? migrate_enable (./arch/x86/include/asm/preempt.h:104 ./include/linux/preempt.h:481 ./include/linux/preempt.h:481 kernel/sched/core.c:2427) 
[ 4114.722207][ C2] ? __pfx_migrate_enable (kernel/sched/core.c:2402) 
[ 4114.722212][ C2] __put_net (net/core/net_namespace.c:732) 
[ 4114.722217][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 4114.722220][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 4114.722223][ C2] rcu_do_batch (./include/linux/rcupdate.h:341 kernel/rcu/tree.c:2578) 
[ 4114.722229][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 4114.722233][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 4114.722236][ C2] ? note_gp_changes (kernel/rcu/tree.c:1326 (discriminator 1)) 
[ 4114.722238][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 4114.722244][ C2] rcu_core (kernel/rcu/tree.c:2834) 
[ 4114.722248][ C2] handle_softirqs (kernel/softirq.c:580) 
[ 4114.722252][ C2] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 4114.722256][ C2] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 4114.722258][ C2] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 4114.722261][ C2] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 4114.722265][ C2] kthread (kernel/kthread.c:464) 
[ 4114.722269][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 4114.722272][ C2] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 4114.722274][ C2] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 4114.722277][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 4114.722280][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 4114.722284][ C2] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 4114.722286][ 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