======================================
| [ 49.019952][ C0] common_startup_64 (arch/x86/kernel/head_64.S:421) 
| [   49.020146][    C0]
| [   49.020226][    C0]
| [   49.020226][    C0] stack backtrace:
[   49.020682][    C0] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[   49.021015][    C0] Call Trace:
[   49.021131][    C0]  <IRQ>
[ 49.021214][ C0] dump_stack_lvl (lib/dump_stack.c:117) 
[ 49.021373][ C0] print_irq_inversion_bug.part.0 (kernel/locking/lockdep.c:4024) 
[ 49.021578][ C0] ? common_startup_64 (arch/x86/kernel/head_64.S:421) 
[ 49.021731][ C0] ? __pfx_print_irq_inversion_bug.part.0 (kernel/locking/lockdep.c:4024) 
[ 49.022020][ C0] ? __pfx_usage_skip (kernel/locking/lockdep.c:2264) 
[ 49.022167][ C0] ? __pfx_usage_match (kernel/locking/lockdep.c:2256) 
[ 49.022345][ C0] ? arch_stack_walk (arch/x86/kernel/stacktrace.c:24) 
[ 49.022496][ C0] mark_lock_irq (kernel/locking/lockdep.c:4244) 
[ 49.022733][ C0] ? __pfx_mark_lock_irq (kernel/locking/lockdep.c:4207) 
[ 49.022891][ C0] ? stack_trace_save (kernel/stacktrace.c:123) 
[ 49.023041][ C0] ? add_chain_cache (kernel/locking/lockdep.c:3730) 
[ 49.023189][ C0] ? save_trace (kernel/locking/lockdep.c:586) 
[ 49.023338][ C0] mark_lock (kernel/locking/lockdep.c:4678) 
[ 49.023633][ C0] mark_usage (kernel/locking/lockdep.c:4567) 
[ 49.023746][ C0] __lock_acquire (kernel/locking/lockdep.c:5091) 
[ 49.023893][ C0] ? __lock_acquire (kernel/locking/lockdep.c:5137) 
[ 49.024041][ C0] ? __pfx_br_forward_delay_timer_expired (net/bridge/br_stp_timer.c:80) bridge
[ 49.024402][ C0] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 49.024560][ C0] ? br_forward_delay_timer_expired (net/bridge/br_stp_timer.c:87) bridge
[ 49.024782][ C0] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 49.024931][ C0] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 49.025170][ C0] ? br_forward_delay_timer_expired (net/bridge/br_stp_timer.c:87) bridge
[ 49.025392][ C0] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 49.025537][ C0] ? br_forward_delay_timer_expired (net/bridge/br_stp_timer.c:87) bridge
[ 49.025766][ C0] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 49.026006][ C0] ? br_forward_delay_timer_expired (net/bridge/br_stp_timer.c:87) bridge
[ 49.026227][ C0] br_forward_delay_timer_expired (net/bridge/br_stp_timer.c:87) bridge
[ 49.026483][ C0] ? __pfx_br_forward_delay_timer_expired (net/bridge/br_stp_timer.c:80) bridge
[ 49.026870][ C0] call_timer_fn (kernel/time/timer.c:1793) 
[ 49.027032][ C0] ? call_timer_fn (./include/linux/lockdep.h:31 kernel/time/timer.c:1783) 
[ 49.027189][ C0] ? call_timer_fn (./include/linux/lockdep.h:31 kernel/time/timer.c:1783) 
[ 49.027342][ C0] ? __pfx_call_timer_fn (kernel/time/timer.c:1770) 
[ 49.027623][ C0] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 49.027741][ C0] __run_timers (kernel/time/timer.c:1845 kernel/time/timer.c:2418) 
[ 49.027889][ C0] ? __pfx_br_forward_delay_timer_expired (net/bridge/br_stp_timer.c:80) bridge
[ 49.028145][ C0] ? __pfx___run_timers (kernel/time/timer.c:2389) 
[ 49.028406][ C0] ? do_raw_spin_lock (./arch/x86/include/asm/atomic.h:115 ./include/linux/atomic/atomic-arch-fallback.h:2170 ./include/linux/atomic/atomic-instrumented.h:1302 ./include/asm-generic/qspinlock.h:111 kernel/locking/spinlock_debug.c:116) 
[ 49.028552][ C0] ? __pfx_do_raw_spin_lock (kernel/locking/spinlock_debug.c:114) 
[ 49.028712][ C0] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 49.028863][ C0] ? run_timer_softirq (kernel/time/timer.c:2429 kernel/time/timer.c:2422 kernel/time/timer.c:2438 kernel/time/timer.c:2448) 
[ 49.029120][ C0] run_timer_softirq (kernel/time/timer.c:2430 kernel/time/timer.c:2422 kernel/time/timer.c:2438 kernel/time/timer.c:2448) 
[ 49.029276][ C0] __do_softirq (kernel/softirq.c:554) 
[ 49.029437][ C0] irq_exit_rcu (kernel/softirq.c:428 kernel/softirq.c:633 kernel/softirq.c:645) 
[ 49.029571][ C0] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1043 arch/x86/kernel/apic/apic.c:1043) 
[   49.029718][    C0]  </IRQ>
[   49.029796][    C0]  <TASK>
[ 49.029903][ C0] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 49.030092][ C0] RIP: 0010:default_idle (./arch/x86/include/asm/irqflags.h:37 ./arch/x86/include/asm/irqflags.h:72 arch/x86/kernel/process.c:743) 
[ 49.030264][ C0] Code: 4c 01 c7 4c 29 c2 e9 72 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d a3 30 35 00 fb f4 <fa> c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90
All code
========
   0:	4c 01 c7             	add    %r8,%rdi
   3:	4c 29 c2             	sub    %r8,%rdx
   6:	e9 72 ff ff ff       	jmp    0xffffffffffffff7d
   b:	90                   	nop
   c:	90                   	nop
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	f3 0f 1e fa          	endbr64
  1f:	66 90                	xchg   %ax,%ax
  21:	0f 00 2d a3 30 35 00 	verw   0x3530a3(%rip)        # 0x3530cb
  28:	fb                   	sti
  29:	f4                   	hlt
  2a:*	fa                   	cli		<-- trapping instruction
  2b:	c3                   	ret
  2c:	cc                   	int3
  2d:	cc                   	int3
  2e:	cc                   	int3
  2f:	cc                   	int3
  30:	66 66 2e 0f 1f 84 00 	data16 cs nopw 0x0(%rax,%rax,1)
  37:	00 00 00 00 
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop

Code starting with the faulting instruction
===========================================
   0:	fa                   	cli
   1:	c3                   	ret
   2:	cc                   	int3
   3:	cc                   	int3
   4:	cc                   	int3
   5:	cc                   	int3
   6:	66 66 2e 0f 1f 84 00 	data16 cs nopw 0x0(%rax,%rax,1)
   d:	00 00 00 00 
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
[   49.030837][    C0] RSP: 0018:ffffffff8c207e00 EFLAGS: 00000242
[   49.031024][    C0] RAX: 00000000000ca5b9 RBX: 1ffffffff1840fc2 RCX: ffffffff8b30e9d5
[   49.031244][    C0] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff88caa4a4
[   49.031470][    C0] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c0709c
[   49.031711][    C0] R10: ffff8880360384e3 R11: ffff88803603dc80 R12: 0000000000000000
[   49.032040][    C0] R13: ffffffff8c21d000 R14: dffffc0000000000 R15: 0000000000014770
[ 49.032286][ C0] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:147) 
[ 49.032469][ C0] ? cpuidle_idle_call (kernel/sched/idle.c:192) 
[ 49.032735][ C0] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 49.032906][ C0] cpuidle_idle_call (kernel/sched/idle.c:192) 
[ 49.033080][ C0] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 49.033228][ C0] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) 
[ 49.033377][ C0] do_idle (kernel/sched/idle.c:332) 
[ 49.033619][ C0] cpu_startup_entry (kernel/sched/idle.c:429 (discriminator 1)) 
[ 49.033765][ C0] rest_init (./include/linux/rcupdate.h:782 init/main.c:703) 
[ 49.033892][ C0] start_kernel (init/main.c:1024 (discriminator 1)) 
[ 49.034044][ C0] x86_64_start_reservations (arch/x86/kernel/head64.c:495) 
[ 49.034410][ C0] x86_64_start_kernel (arch/x86/kernel/head64.c:437 (discriminator 17)) 


Finger prints:
common_startup_64:dump_stack_lvl:mark_lock_irq:mark_lock