======================================
| [   16.455451][    C2] 1 lock held by ksoftirqd/2/27:
| [ 16.455643][ C2] #0: ffffffff8e7774c0 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2570) 
| [   16.455988][    C2]
| [   16.455988][    C2] stack backtrace:
[   16.456238][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   16.456240][    C2] Call Trace:
[   16.456242][    C2]  <TASK>
[ 16.456246][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 16.456252][ C2] print_usage_bug.part.0 (kernel/locking/lockdep.c:4048) 
[ 16.456258][ C2] mark_lock_irq (kernel/locking/lockdep.c:4013 kernel/locking/lockdep.c:4059 kernel/locking/lockdep.c:4270) 
[ 16.456262][ C2] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 16.456268][ C2] ? save_trace (kernel/locking/lockdep.c:595) 
[ 16.456272][ C2] mark_lock (kernel/locking/lockdep.c:4756) 
[ 16.456276][ C2] mark_usage (kernel/locking/lockdep.c:4645) 
[ 16.456279][ C2] __lock_acquire (kernel/locking/lockdep.c:5194) 
[ 16.456283][ C2] ? __lock_acquire (kernel/locking/lockdep.c:5240) 
[ 16.456287][ C2] lock_acquire.part.0 (kernel/locking/lockdep.c:473 kernel/locking/lockdep.c:5873) 
[ 16.456291][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 16.456295][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 16.456299][ C2] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5834) 
[ 16.456302][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 16.456306][ C2] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 16.456309][ C2] ? simple_pin_fs (fs/libfs.c:1067) 
[ 16.456312][ C2] simple_pin_fs (fs/libfs.c:1067) 
[ 16.456315][ C2] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 16.456319][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 16.456324][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 16.456326][ 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) 
[ 16.456332][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 16.456335][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 16.456337][ C2] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 16.456341][ C2] ? kthread (kernel/kthread.c:464) 
[ 16.456344][ C2] ? ret_from_fork (arch/x86/kernel/process.c:148) 
[ 16.456348][ C2] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 16.456350][ 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) 
[ 16.456355][ C2] ? __pfx_migrate_enable (kernel/sched/core.c:2402) 
[ 16.456360][ C2] __put_net (net/core/net_namespace.c:732) 
[ 16.456365][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 16.456369][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 16.456372][ C2] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 16.456376][ C2] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 16.456380][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 16.456384][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 16.456387][ C2] ? note_gp_changes (kernel/rcu/tree.c:1326 (discriminator 1)) 
[ 16.456390][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 16.456396][ C2] rcu_core (kernel/rcu/tree.c:2834) 
[ 16.456401][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 16.456406][ C2] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 16.456410][ C2] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 16.456413][ C2] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 16.456416][ C2] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 16.456419][ C2] kthread (kernel/kthread.c:464) 
[ 16.456422][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 16.456425][ C2] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 16.456427][ C2] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 16.456431][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 16.456435][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 16.456438][ C2] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 16.456441][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 16.456444][ C2] ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
| [   16.469167][    C2] RCU nest depth: 0, expected: 0
| [   16.469462][    C2] INFO: lockdep is turned off.
| [   16.469763][    C2] Preemption disabled at:
| [ 16.469767][ C2] handle_softirqs (kernel/softirq.c:553) 
[   16.470597][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   16.470601][    C2] Call Trace:
[   16.470604][    C2]  <TASK>
[ 16.470609][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 16.470620][ C2] __might_resched (kernel/sched/core.c:8796) 
[ 16.470630][ C2] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 16.470636][ C2] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 16.470640][ C2] ? simple_recursive_removal (fs/libfs.c:614) 
[ 16.470646][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 16.470654][ 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) 
[ 16.470661][ C2] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:617) 
[ 16.470666][ 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) 
[ 16.470670][ C2] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 16.470680][ C2] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 16.470686][ C2] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 16.470693][ C2] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 16.470697][ 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) 
[ 16.470705][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 16.470711][ C2] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 16.470716][ C2] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 16.470721][ C2] ? kthread (kernel/kthread.c:464) 
[ 16.470726][ C2] ? ret_from_fork (arch/x86/kernel/process.c:148) 
[ 16.470732][ C2] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 16.470738][ 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) 
[ 16.470745][ C2] ? __pfx_migrate_enable (kernel/sched/core.c:2402) 
[ 16.470755][ C2] __put_net (net/core/net_namespace.c:732) 
[ 16.470761][ C2] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 16.470768][ C2] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 16.470773][ C2] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 16.470779][ C2] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 16.470788][ C2] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 16.470794][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 16.470799][ C2] ? note_gp_changes (kernel/rcu/tree.c:1326 (discriminator 1)) 
[ 16.470805][ C2] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 16.470815][ C2] rcu_core (kernel/rcu/tree.c:2834) 
[ 16.470823][ C2] handle_softirqs (kernel/softirq.c:579) 
[ 16.470832][ C2] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 16.470839][ C2] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 16.470844][ C2] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 16.470850][ C2] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 16.470856][ C2] kthread (kernel/kthread.c:464) 
[ 16.470862][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 16.470866][ C2] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 16.470871][ C2] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 16.470877][ C2] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 16.470882][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 16.470888][ C2] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 16.470894][ C2] ? __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