======================================
| xx__-> echo $?
| 0
| xx__->
| [  957.252050][    C3] irq 4: nobody cared (try booting with the "irqpoll" option)
[  957.252687][    C3] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  957.253054][    C3] Call Trace:
[  957.253191][    C3]  <IRQ>
[ 957.253286][ C3] dump_stack_lvl (lib/dump_stack.c:117) 
[ 957.253475][ C3] __report_bad_irq (kernel/irq/spurious.c:214) 
[ 957.253652][ C3] note_interrupt (kernel/irq/spurious.c:423) 
[ 957.253841][ C3] handle_irq_event (kernel/irq/handle.c:198 kernel/irq/handle.c:210) 
[ 957.254015][ C3] handle_edge_irq (kernel/irq/chip.c:833) 
[ 957.254187][ C3] __common_interrupt (./include/linux/irqdesc.h:173 arch/x86/kernel/irq.c:247 arch/x86/kernel/irq.c:259 arch/x86/kernel/irq.c:285) 
[ 957.254344][ C3] common_interrupt (arch/x86/kernel/irq.c:278 (discriminator 14)) 
[  957.254515][    C3]  </IRQ>
[  957.254598][    C3]  <TASK>
[ 957.254679][ C3] asm_common_interrupt (./arch/x86/include/asm/idtentry.h:693) 
[ 957.254837][ C3] RIP: 0010:_raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 957.255044][ C3] Code: 10 e8 d1 c0 93 fd 48 89 ef e8 49 31 94 fd 81 e3 00 02 00 00 75 1d 9c 58 f6 c4 02 75 29 48 85 db 74 01 fb 65 ff 0d 45 21 68 6d <74> 0e 5b 5d c3 cc cc cc cc e8 ef a0 b7 fd eb dc 0f 1f 44 00 00 5b
All code
========
   0:	10 e8                	adc    %ch,%al
   2:	d1 c0                	rol    %eax
   4:	93                   	xchg   %eax,%ebx
   5:	fd                   	std
   6:	48 89 ef             	mov    %rbp,%rdi
   9:	e8 49 31 94 fd       	call   0xfffffffffd943157
   e:	81 e3 00 02 00 00    	and    $0x200,%ebx
  14:	75 1d                	jne    0x33
  16:	9c                   	pushf
  17:	58                   	pop    %rax
  18:	f6 c4 02             	test   $0x2,%ah
  1b:	75 29                	jne    0x46
  1d:	48 85 db             	test   %rbx,%rbx
  20:	74 01                	je     0x23
  22:	fb                   	sti
  23:	65 ff 0d 45 21 68 6d 	decl   %gs:0x6d682145(%rip)        # 0x6d68216f
  2a:*	74 0e                	je     0x3a		<-- trapping instruction
  2c:	5b                   	pop    %rbx
  2d:	5d                   	pop    %rbp
  2e:	c3                   	ret
  2f:	cc                   	int3
  30:	cc                   	int3
  31:	cc                   	int3
  32:	cc                   	int3
  33:	e8 ef a0 b7 fd       	call   0xfffffffffdb7a127
  38:	eb dc                	jmp    0x16
  3a:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  3f:	5b                   	pop    %rbx

Code starting with the faulting instruction
===========================================
   0:	74 0e                	je     0x10
   2:	5b                   	pop    %rbx
   3:	5d                   	pop    %rbp
   4:	c3                   	ret
   5:	cc                   	int3
   6:	cc                   	int3
   7:	cc                   	int3
   8:	cc                   	int3
   9:	e8 ef a0 b7 fd       	call   0xfffffffffdb7a0fd
   e:	eb dc                	jmp    0xffffffffffffffec
  10:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  15:	5b                   	pop    %rbx
[  957.255623][    C3] RSP: 0018:ffffc90000b7fac0 EFLAGS: 00000286
[  957.255848][    C3] RAX: 0000000000000002 RBX: 0000000000000200 RCX: 1ffffffff2b6ef65
[  957.256102][    C3] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff929ba6d1
[  957.256361][    C3] RBP: ffffffff96439020 R08: 0000000000000001 R09: fffffbfff2b6a0a8
[  957.256629][    C3] R10: ffffffff95b50547 R11: 0000000000000000 R12: 0000000000000001
[  957.256886][    C3] R13: 0000000000000282 R14: ffffffff96439020 R15: ffff88800281a000
[ 957.257150][ C3] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 957.257373][ C3] uart_write (drivers/tty/serial/serial_core.c:74 drivers/tty/serial/serial_core.c:634) 
[ 957.257507][ C3] process_output_block (drivers/tty/n_tty.c:574) 
[ 957.257679][ C3] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4300 kernel/locking/lockdep.c:4359) 
[ 957.257903][ C3] n_tty_write (drivers/tty/n_tty.c:2380) 
[ 957.258086][ C3] ? __pfx_n_tty_write (drivers/tty/n_tty.c:2350) 
[ 957.258262][ C3] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 957.258429][ C3] ? __pfx_woken_wake_function (kernel/sched/wait.c:439) 
[ 957.258603][ C3] ? iterate_tty_write (drivers/tty/tty_io.c:954 drivers/tty/tty_io.c:973) 
[ 957.258775][ C3] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 957.258937][ C3] ? iterate_tty_write (drivers/tty/tty_io.c:954 drivers/tty/tty_io.c:973) 
[ 957.259115][ C3] iterate_tty_write (drivers/tty/tty_io.c:1021) 
[ 957.259273][ C3] ? tty_ldisc_ref_wait (drivers/tty/tty_ldisc.c:244) 
[ 957.259441][ C3] file_tty_write.constprop.0 (drivers/tty/tty_io.c:1096) 
[ 957.259617][ C3] vfs_write (fs/read_write.c:497 fs/read_write.c:590) 
[ 957.259751][ C3] ? __pfx___lock_release (kernel/locking/lockdep.c:5406) 
[ 957.259914][ C3] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 957.260087][ C3] ? __might_fault (mm/memory.c:6233 mm/memory.c:6226) 
[ 957.260245][ C3] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 957.260413][ C3] ? __pfx_vfs_write (fs/read_write.c:571) 
[ 957.260588][ C3] ? __might_fault (mm/memory.c:6233 mm/memory.c:6226) 
[ 957.260760][ C3] ? __rseq_handle_notify_resume (kernel/rseq.c:316) 
[ 957.260954][ C3] ? __fget_light (./include/linux/atomic/atomic-arch-fallback.h:479 ./include/linux/atomic/atomic-instrumented.h:50 fs/file.c:1145) 
[ 957.261132][ C3] ksys_write (fs/read_write.c:643) 
[ 957.261260][ C3] ? __pfx_ksys_write (fs/read_write.c:633) 
[ 957.261458][ C3] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
[ 957.261624][ C3] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
[  957.261818][    C3] RIP: 0033:0x7f6dd4954957
[ 957.261992][ C3] Code: 0b 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
All code
========
   0:	0b 00                	or     (%rax),%eax
   2:	f7 d8                	neg    %eax
   4:	64 89 02             	mov    %eax,%fs:(%rdx)
   7:	48 c7 c0 ff ff ff ff 	mov    $0xffffffffffffffff,%rax
   e:	eb b7                	jmp    0xffffffffffffffc7
  10:	0f 1f 00             	nopl   (%rax)
  13:	f3 0f 1e fa          	endbr64
  17:	64 8b 04 25 18 00 00 	mov    %fs:0x18,%eax
  1e:	00 
  1f:	85 c0                	test   %eax,%eax
  21:	75 10                	jne    0x33
  23:	b8 01 00 00 00       	mov    $0x1,%eax
  28:	0f 05                	syscall
  2a:*	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax		<-- trapping instruction
  30:	77 51                	ja     0x83
  32:	c3                   	ret
  33:	48 83 ec 28          	sub    $0x28,%rsp
  37:	48 89 54 24 18       	mov    %rdx,0x18(%rsp)
  3c:	48                   	rex.W
  3d:	89                   	.byte 0x89
  3e:	74 24                	je     0x64

Code starting with the faulting instruction
===========================================
   0:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   6:	77 51                	ja     0x59
   8:	c3                   	ret
   9:	48 83 ec 28          	sub    $0x28,%rsp
   d:	48 89 54 24 18       	mov    %rdx,0x18(%rsp)
  12:	48                   	rex.W
  13:	89                   	.byte 0x89
  14:	74 24                	je     0x3a
[  957.262554][    C3] RSP: 002b:00007fffd4a82558 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[  957.262823][    C3] RAX: ffffffffffffffda RBX: 000055d7e39c3310 RCX: 00007f6dd4954957
[  957.263086][    C3] RDX: 0000000000000001 RSI: 000055d7e39c3310 RDI: 0000000000000001
[  957.263338][    C3] RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000002000
[  957.263600][    C3] R10: 0000000000000001 R11: 0000000000000246 R12: 000055d7e39af5c0


Finger prints:
__report_bad_irq:note_interrupt:handle_irq_event:handle_edge_irq:__common_interrupt