======================================
| [ 4339.506890][    C2] 1 lock held by swapper/2/0:
| [ 4339.507023][ C2] #0: ffffc90000230d68 ((&tw->tw_timer)){+.-.}-{0:0}, at: call_timer_fn (./include/linux/lockdep.h:31 kernel/time/timer.c:1783) 
| [ 4339.507264][    C2]
| [ 4339.507264][    C2] stack backtrace:
[ 4339.507631][    C2] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 4339.507934][    C2] Call Trace:
[ 4339.508038][    C2]  <IRQ>
[ 4339.508108][ C2] dump_stack_lvl (lib/dump_stack.c:117) 
[ 4339.508255][ C2] check_noncircular (kernel/locking/lockdep.c:2187) 
[ 4339.508467][ C2] ? __pfx_check_noncircular (kernel/locking/lockdep.c:2163) 
[ 4339.508602][ C2] ? common_startup_64 (arch/x86/kernel/head_64.S:421) 
[ 4339.508735][ C2] ? alloc_chain_hlocks (kernel/locking/lockdep.c:3501) 
[ 4339.508871][ C2] check_prev_add (kernel/locking/lockdep.c:3135) 
[ 4339.509080][ C2] validate_chain (kernel/locking/lockdep.c:3254 kernel/locking/lockdep.c:3869) 
[ 4339.509216][ C2] ? __pfx_validate_chain (kernel/locking/lockdep.c:3825) 
[ 4339.509424][ C2] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228) 
[ 4339.509553][ C2] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 4339.509658][ C2] __lock_acquire (kernel/locking/lockdep.c:5137) 
[ 4339.509876][ C2] ? __pfx_tw_timer_handler (net/ipv4/inet_timewait_sock.c:173) 
[ 4339.510012][ C2] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 4339.510150][ C2] ? tw_timer_handler (net/ipv4/inet_timewait_sock.c:81 net/ipv4/inet_timewait_sock.c:176) 
[ 4339.510288][ C2] ? __pfx_tw_timer_handler (net/ipv4/inet_timewait_sock.c:173) 
[ 4339.510497][ C2] ? lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 4339.510632][ C2] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 4339.510771][ C2] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 4339.510992][ C2] ? tw_timer_handler (net/ipv4/inet_timewait_sock.c:81 net/ipv4/inet_timewait_sock.c:176) 
[ 4339.511126][ C2] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 4339.511259][ C2] ? tw_timer_handler (net/ipv4/inet_timewait_sock.c:81 net/ipv4/inet_timewait_sock.c:176) 
[ 4339.511475][ C2] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 4339.511609][ C2] ? tw_timer_handler (net/ipv4/inet_timewait_sock.c:81 net/ipv4/inet_timewait_sock.c:176) 
[ 4339.511742][ C2] tw_timer_handler (net/ipv4/inet_timewait_sock.c:81 net/ipv4/inet_timewait_sock.c:176) 
[ 4339.511959][ C2] call_timer_fn (kernel/time/timer.c:1793) 
[ 4339.512103][ C2] ? call_timer_fn (./include/linux/lockdep.h:31 kernel/time/timer.c:1783) 
[ 4339.512232][ C2] ? call_timer_fn (./include/linux/lockdep.h:31 kernel/time/timer.c:1783) 
[ 4339.512376][ C2] ? __pfx_call_timer_fn (kernel/time/timer.c:1770) 
[ 4339.512590][ C2] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 4339.512699][ C2] __run_timers (kernel/time/timer.c:1845 kernel/time/timer.c:2418) 
[ 4339.512838][ C2] ? __pfx_tw_timer_handler (net/ipv4/inet_timewait_sock.c:173) 
[ 4339.512976][ C2] ? __pfx___run_timers (kernel/time/timer.c:2389) 
[ 4339.513188][ C2] ? 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) 
[ 4339.513319][ C2] ? __pfx_do_raw_spin_lock (kernel/locking/spinlock_debug.c:114) 
[ 4339.513452][ C2] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 4339.513589][ C2] ? run_timer_softirq (kernel/time/timer.c:2429 kernel/time/timer.c:2422 kernel/time/timer.c:2438 kernel/time/timer.c:2446) 
[ 4339.513731][ C2] run_timer_softirq (kernel/time/timer.c:2430 kernel/time/timer.c:2422 kernel/time/timer.c:2438 kernel/time/timer.c:2446) 
[ 4339.513958][ C2] __do_softirq (kernel/softirq.c:554) 
[ 4339.514094][ C2] irq_exit_rcu (kernel/softirq.c:428 kernel/softirq.c:633 kernel/softirq.c:645) 
[ 4339.514205][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1043 arch/x86/kernel/apic/apic.c:1043) 
[ 4339.514336][    C2]  </IRQ>
[ 4339.514405][    C2]  <TASK>
[ 4339.514549][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 4339.514711][ C2] RIP: 0010:default_idle (./arch/x86/include/asm/irqflags.h:37 ./arch/x86/include/asm/irqflags.h:72 arch/x86/kernel/process.c:743) 
[ 4339.514851][ C2] 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 23 8d 32 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 23 8d 32 00 	verw   0x328d23(%rip)        # 0x328d4b
  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
[ 4339.515489][    C2] RSP: 0018:ffffc9000015fdf8 EFLAGS: 00000246
[ 4339.515664][    C2] RAX: 0000000007289ff5 RBX: 1ffff9200002bfc1 RCX: ffffffffa1b38e55
[ 4339.515944][    C2] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff9f2ac0e4
[ 4339.516139][    C2] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c2709c
[ 4339.516335][    C2] R10: ffff8880361384e3 R11: 1ffff110003ab28c R12: 0000000000000000
[ 4339.516610][    C2] R13: ffff888001b8c5c0 R14: dffffc0000000000 R15: 0000000000000000
[ 4339.516893][ C2] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:147) 
[ 4339.517022][ C2] ? cpuidle_idle_call (kernel/sched/idle.c:192) 
[ 4339.517155][ C2] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 4339.517287][ C2] cpuidle_idle_call (kernel/sched/idle.c:192) 
[ 4339.517419][ C2] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 4339.517549][ C2] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) 
[ 4339.517691][ C2] do_idle (kernel/sched/idle.c:332) 
[ 4339.517794][ C2] cpu_startup_entry (kernel/sched/idle.c:429 (discriminator 1)) 
[ 4339.517926][ C2] start_secondary (arch/x86/kernel/smpboot.c:201 arch/x86/kernel/smpboot.c:281) 
[ 4339.518139][ C2] ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:231) 


Finger prints:
dump_stack_lvl:check_noncircular:check_prev_add:validate_chain