======================================
| [   13.059650][    C3] 1 lock held by ksoftirqd/3/32:
| [ 13.059853][ C3] #0: ffffffffb8b774c0 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2570) 
| [   13.060219][    C3]
| [   13.060219][    C3] stack backtrace:
[   13.060481][    C3] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.060483][    C3] Call Trace:
[   13.060485][    C3]  <TASK>
[ 13.060488][ C3] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.060493][ C3] print_usage_bug.part.0 (kernel/locking/lockdep.c:4048) 
[ 13.060498][ C3] mark_lock_irq (kernel/locking/lockdep.c:4013 kernel/locking/lockdep.c:4059 kernel/locking/lockdep.c:4270) 
[ 13.060503][ C3] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 13.060508][ C3] ? save_trace (kernel/locking/lockdep.c:595) 
[ 13.060512][ C3] mark_lock (kernel/locking/lockdep.c:4756) 
[ 13.060516][ C3] mark_usage (kernel/locking/lockdep.c:4645) 
[ 13.060519][ C3] __lock_acquire (kernel/locking/lockdep.c:5194) 
[ 13.060523][ C3] ? __lock_acquire (kernel/locking/lockdep.c:5240) 
[ 13.060527][ C3] lock_acquire.part.0 (kernel/locking/lockdep.c:473 kernel/locking/lockdep.c:5873) 
[ 13.060530][ C3] ? simple_pin_fs (fs/libfs.c:1067) 
[ 13.060534][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.060539][ C3] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5834) 
[ 13.060542][ C3] ? simple_pin_fs (fs/libfs.c:1067) 
[ 13.060545][ C3] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 13.060548][ C3] ? simple_pin_fs (fs/libfs.c:1067) 
[ 13.060551][ C3] simple_pin_fs (fs/libfs.c:1067) 
[ 13.060554][ C3] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 13.060557][ C3] ref_tracker_dir_exit (lib/ref_tracker.c:411 lib/ref_tracker.c:195) 
[ 13.060562][ C3] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 13.060565][ 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) 
[ 13.060570][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.060573][ C3] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 13.060575][ C3] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.060579][ C3] ? kthread (kernel/kthread.c:464) 
[ 13.060582][ C3] ? ret_from_fork (arch/x86/kernel/process.c:148) 
[ 13.060586][ C3] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 13.060588][ 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) 
[ 13.060592][ C3] ? __pfx_migrate_enable (kernel/sched/core.c:2402) 
[ 13.060598][ C3] __put_net (net/core/net_namespace.c:732) 
[ 13.060602][ C3] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 13.060606][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.060608][ C3] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.060612][ C3] ? __schedule (kernel/sched/core.c:6658) 
[ 13.060617][ C3] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 13.060621][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.060624][ C3] ? note_gp_changes (kernel/rcu/tree.c:1326 (discriminator 1)) 
[ 13.060627][ C3] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 13.060633][ C3] rcu_core (kernel/rcu/tree.c:2834) 
[ 13.060638][ C3] handle_softirqs (kernel/softirq.c:579) 
[ 13.060642][ C3] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 13.060646][ C3] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 13.060649][ C3] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.060652][ C3] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 13.060655][ C3] kthread (kernel/kthread.c:464) 
[ 13.060658][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.060661][ C3] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 13.060663][ C3] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 13.060667][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.060670][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.060674][ C3] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 13.060676][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.060679][ C3] ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
| [   13.073159][    C3] RCU nest depth: 0, expected: 0
| [   13.073345][    C3] INFO: lockdep is turned off.
| [   13.073532][    C3] Preemption disabled at:
| [ 13.073534][ C3] handle_softirqs (kernel/softirq.c:553) 
[   13.073928][    C3] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.073929][    C3] Call Trace:
[   13.073931][    C3]  <TASK>
[ 13.073932][ C3] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.073938][ C3] __might_resched (kernel/sched/core.c:8796) 
[ 13.073945][ C3] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 13.073948][ C3] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 13.073951][ C3] ? simple_recursive_removal (fs/libfs.c:614) 
[ 13.073955][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.073959][ 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) 
[ 13.073963][ C3] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:617) 
[ 13.073966][ 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) 
[ 13.073969][ C3] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 13.073974][ C3] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 13.073977][ C3] ref_tracker_dir_exit (lib/ref_tracker.c:411 lib/ref_tracker.c:195) 
[ 13.073981][ C3] ? __pfx_ref_tracker_free (lib/ref_tracker.c:253) 
[ 13.073983][ 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) 
[ 13.073987][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.073990][ C3] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:189) 
[ 13.073993][ C3] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.073995][ C3] ? kthread (kernel/kthread.c:464) 
[ 13.073998][ C3] ? ret_from_fork (arch/x86/kernel/process.c:148) 
[ 13.074001][ C3] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 13.074004][ 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) 
[ 13.074008][ C3] ? __pfx_migrate_enable (kernel/sched/core.c:2402) 
[ 13.074013][ C3] __put_net (net/core/net_namespace.c:732) 
[ 13.074017][ C3] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 13.074021][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.074023][ C3] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.074027][ C3] ? __schedule (kernel/sched/core.c:6658) 
[ 13.074032][ C3] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 13.074036][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.074039][ C3] ? note_gp_changes (kernel/rcu/tree.c:1326 (discriminator 1)) 
[ 13.074042][ C3] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 13.074047][ C3] rcu_core (kernel/rcu/tree.c:2834) 
[ 13.074051][ C3] handle_softirqs (kernel/softirq.c:579) 
[ 13.074055][ C3] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 13.074059][ C3] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 13.074062][ C3] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.074065][ C3] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 13.074068][ C3] kthread (kernel/kthread.c:464) 
[ 13.074071][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.074074][ C3] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 13.074077][ C3] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 13.074082][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.074085][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.074088][ C3] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 13.074092][ C3] ? __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