======================================
| [  132.221770] ------------[ cut here ]------------
| [  132.222044] refcount_t: underflow; use-after-free.
| [  132.222315] WARNING: CPU: 0 PID: 11 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3)) 
| [  132.222746] Modules linked in:
[  132.223276] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  132.223849] Workqueue: netns cleanup_net
[  132.224057] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3)) 
[ 132.224322] Code: 0b 90 90 c3 cc cc cc cc 80 3d 69 d4 67 01 00 0f 85 75 ff ff ff c6 05 5c d4 67 01 01 90 48 c7 c7 e8 37 b3 b6 e8 a1 26 b4 ff 90 <0f> 0b 90 90 c3 cc cc cc cc 80 3d 3c d4 67 01 00 0f 85 4a ff ff ff
All code
========
   0:	0b 90 90 c3 cc cc    	or     -0x33333c70(%rax),%edx
   6:	cc                   	int3
   7:	cc                   	int3
   8:	80 3d 69 d4 67 01 00 	cmpb   $0x0,0x167d469(%rip)        # 0x167d478
   f:	0f 85 75 ff ff ff    	jne    0xffffffffffffff8a
  15:	c6 05 5c d4 67 01 01 	movb   $0x1,0x167d45c(%rip)        # 0x167d478
  1c:	90                   	nop
  1d:	48 c7 c7 e8 37 b3 b6 	mov    $0xffffffffb6b337e8,%rdi
  24:	e8 a1 26 b4 ff       	call   0xffffffffffb426ca
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	c3                   	ret
  2f:	cc                   	int3
  30:	cc                   	int3
  31:	cc                   	int3
  32:	cc                   	int3
  33:	80 3d 3c d4 67 01 00 	cmpb   $0x0,0x167d43c(%rip)        # 0x167d476
  3a:	0f 85 4a ff ff ff    	jne    0xffffffffffffff8a

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	90                   	nop
   4:	c3                   	ret
   5:	cc                   	int3
   6:	cc                   	int3
   7:	cc                   	int3
   8:	cc                   	int3
   9:	80 3d 3c d4 67 01 00 	cmpb   $0x0,0x167d43c(%rip)        # 0x167d44c
  10:	0f 85 4a ff ff ff    	jne    0xffffffffffffff60
[  132.225243] RSP: 0018:ffffae7900063d78 EFLAGS: 00010286
[  132.225517] RAX: 0000000000000000 RBX: ffff8959843cc000 RCX: 00000000ffffdfff
[  132.225877] RDX: 0000000000000000 RSI: 00000000ffffffea RDI: 0000000000000001
[  132.226246] RBP: ffff8959843cc610 R08: ffffffffb6f78508 R09: 00000000ffffdfff
[  132.226612] R10: ffffffffb6e98520 R11: ffffffffb6f48520 R12: ffff8959843cc000
[  132.226970] R13: ffffae7900063e08 R14: ffff8959843ccb80 R15: ffff895984322e50
[  132.227338] FS:  0000000000000000(0000) GS:ffff8959bec00000(0000) knlGS:0000000000000000
[  132.227770] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  132.228085] CR2: 00007fa35f73b1b4 CR3: 0000000004f1c003 CR4: 0000000000770ef0
[  132.228454] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  132.228821] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  132.229191] PKRU: 55555554
[  132.229338] Call Trace:
[  132.229484]  <TASK>
[  132.229607] ? __warn (kernel/panic.c:677) 
[  132.229785] ? refcount_warn_saturate (lib/refcount.c:28 (discriminator 3)) 
[  132.230028] ? report_bug (lib/bug.c:201 lib/bug.c:219) 
[  132.230227] ? handle_bug (arch/x86/kernel/traps.c:238) 
[  132.230417] ? exc_invalid_op (arch/x86/kernel/traps.c:259 (discriminator 1)) 
[  132.230631] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:568) 
[  132.230859] ? refcount_warn_saturate (lib/refcount.c:28 (discriminator 3)) 
[  132.231101] ? refcount_warn_saturate (lib/refcount.c:28 (discriminator 3)) 
[  132.231343] br_sysfs_delbr (net/bridge/br_sysfs_br.c:1086) 
[  132.231564] br_dev_delete (net/bridge/br_if.c:396) 
[  132.231754] br_net_exit_batch_rtnl (net/bridge/br.c:369) 
[  132.231982] cleanup_net (net/core/net_namespace.c:630) 
[  132.232173] ? process_one_work (kernel/workqueue.c:2606) 
[  132.232390] process_one_work (kernel/workqueue.c:2633) 
[  132.232603] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[  132.232799] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[  132.233020] kthread (kernel/kthread.c:388) 
[  132.233188] ? __pfx_kthread (kernel/kthread.c:341) 
[  132.233384] ret_from_fork (arch/x86/kernel/process.c:147) 
[  132.233580] ? __pfx_kthread (kernel/kthread.c:341) 
[  132.233774] ret_from_fork_asm (arch/x86/entry/entry_64.S:250) 
| [  132.236323] ------------[ cut here ]------------
| [  132.236632] sysfs group 'bridge' not found for kobject 'br0'
| [  132.236944] WARNING: CPU: 0 PID: 11 at fs/sysfs/group.c:282 sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
| [  132.237389] Modules linked in:
[  132.238077] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  132.238699] Workqueue: netns cleanup_net
[  132.238944] RIP: 0010:sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
[ 132.239229] Code: 48 89 ef 5d 41 5c e9 7a ad ff ff 48 89 ef e8 12 9b ff ff eb d1 90 49 8b 14 24 48 8b 33 48 c7 c7 d0 cd b2 b6 e8 ac 67 c5 ff 90 <0f> 0b 90 90 5b 5d 41 5c c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00
All code
========
   0:	48 89 ef             	mov    %rbp,%rdi
   3:	5d                   	pop    %rbp
   4:	41 5c                	pop    %r12
   6:	e9 7a ad ff ff       	jmp    0xffffffffffffad85
   b:	48 89 ef             	mov    %rbp,%rdi
   e:	e8 12 9b ff ff       	call   0xffffffffffff9b25
  13:	eb d1                	jmp    0xffffffffffffffe6
  15:	90                   	nop
  16:	49 8b 14 24          	mov    (%r12),%rdx
  1a:	48 8b 33             	mov    (%rbx),%rsi
  1d:	48 c7 c7 d0 cd b2 b6 	mov    $0xffffffffb6b2cdd0,%rdi
  24:	e8 ac 67 c5 ff       	call   0xffffffffffc567d5
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	5b                   	pop    %rbx
  2f:	5d                   	pop    %rbp
  30:	41 5c                	pop    %r12
  32:	c3                   	ret
  33:	cc                   	int3
  34:	cc                   	int3
  35:	cc                   	int3
  36:	cc                   	int3
  37:	66                   	data16
  38:	66                   	data16
  39:	2e                   	cs
  3a:	0f                   	.byte 0xf
  3b:	1f                   	(bad)
  3c:	84 00                	test   %al,(%rax)
	...

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	90                   	nop
   4:	5b                   	pop    %rbx
   5:	5d                   	pop    %rbp
   6:	41 5c                	pop    %r12
   8:	c3                   	ret
   9:	cc                   	int3
   a:	cc                   	int3
   b:	cc                   	int3
   c:	cc                   	int3
   d:	66                   	data16
   e:	66                   	data16
   f:	2e                   	cs
  10:	0f                   	.byte 0xf
  11:	1f                   	(bad)
  12:	84 00                	test   %al,(%rax)
	...
[  132.240217] RSP: 0018:ffffae7900063d70 EFLAGS: 00010286
[  132.240534] RAX: 0000000000000000 RBX: ffffffffb67472c0 RCX: 00000000ffffdfff
[  132.240948] RDX: 0000000000000000 RSI: 00000000ffffffea RDI: 0000000000000001
[  132.241387] RBP: 0000000000000000 R08: ffffffffb6f78508 R09: 00000000ffffdfff
[  132.241888] R10: ffffffffb6e98520 R11: ffffffffb6f48520 R12: ffff8959843cc610
[  132.242362] R13: ffffae7900063e08 R14: ffff8959843ccb80 R15: ffff895984322e50
[  132.242809] FS:  0000000000000000(0000) GS:ffff8959bec00000(0000) knlGS:0000000000000000
[  132.243282] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  132.243655] CR2: 00007fa35f73b1b4 CR3: 0000000004f1c003 CR4: 0000000000770ef0
[  132.244087] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  132.244477] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  132.244919] PKRU: 55555554
[  132.245112] Call Trace:
[  132.245317]  <TASK>
[  132.245483] ? __warn (kernel/panic.c:677) 
[  132.245701] ? sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
[  132.245968] ? report_bug (lib/bug.c:201 lib/bug.c:219) 
[  132.246198] ? handle_bug (arch/x86/kernel/traps.c:238) 
[  132.246443] ? exc_invalid_op (arch/x86/kernel/traps.c:259 (discriminator 1)) 
[  132.246685] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:568) 
[  132.246950] ? sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
[  132.247217] br_dev_delete (net/bridge/br_if.c:396) 
[  132.247457] br_net_exit_batch_rtnl (net/bridge/br.c:369) 
[  132.247727] cleanup_net (net/core/net_namespace.c:630) 
[  132.247965] ? process_one_work (kernel/workqueue.c:2606) 
[  132.248254] process_one_work (kernel/workqueue.c:2633) 
[  132.248515] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[  132.248751] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[  132.249105] kthread (kernel/kthread.c:388) 
[  132.249333] ? __pfx_kthread (kernel/kthread.c:341) 
[  132.249582] ret_from_fork (arch/x86/kernel/process.c:147) 
[  132.249835] ? __pfx_kthread (kernel/kthread.c:341) 
[  132.250062] ret_from_fork_asm (arch/x86/entry/entry_64.S:250) 
| [  144.699377] ------------[ cut here ]------------
| [  144.699703] sysfs group 'bridge' not found for kobject 'br0'
| [  144.700046] WARNING: CPU: 1 PID: 11 at fs/sysfs/group.c:282 sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
| [  144.700474] Modules linked in:
[  144.701102] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  144.701776] Workqueue: netns cleanup_net
[  144.701987] RIP: 0010:sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
[ 144.702248] Code: 48 89 ef 5d 41 5c e9 7a ad ff ff 48 89 ef e8 12 9b ff ff eb d1 90 49 8b 14 24 48 8b 33 48 c7 c7 d0 cd b2 b6 e8 ac 67 c5 ff 90 <0f> 0b 90 90 5b 5d 41 5c c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00
All code
========
   0:	48 89 ef             	mov    %rbp,%rdi
   3:	5d                   	pop    %rbp
   4:	41 5c                	pop    %r12
   6:	e9 7a ad ff ff       	jmp    0xffffffffffffad85
   b:	48 89 ef             	mov    %rbp,%rdi
   e:	e8 12 9b ff ff       	call   0xffffffffffff9b25
  13:	eb d1                	jmp    0xffffffffffffffe6
  15:	90                   	nop
  16:	49 8b 14 24          	mov    (%r12),%rdx
  1a:	48 8b 33             	mov    (%rbx),%rsi
  1d:	48 c7 c7 d0 cd b2 b6 	mov    $0xffffffffb6b2cdd0,%rdi
  24:	e8 ac 67 c5 ff       	call   0xffffffffffc567d5
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	5b                   	pop    %rbx
  2f:	5d                   	pop    %rbp
  30:	41 5c                	pop    %r12
  32:	c3                   	ret
  33:	cc                   	int3
  34:	cc                   	int3
  35:	cc                   	int3
  36:	cc                   	int3
  37:	66                   	data16
  38:	66                   	data16
  39:	2e                   	cs
  3a:	0f                   	.byte 0xf
  3b:	1f                   	(bad)
  3c:	84 00                	test   %al,(%rax)
	...

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	90                   	nop
   4:	5b                   	pop    %rbx
   5:	5d                   	pop    %rbp
   6:	41 5c                	pop    %r12
   8:	c3                   	ret
   9:	cc                   	int3
   a:	cc                   	int3
   b:	cc                   	int3
   c:	cc                   	int3
   d:	66                   	data16
   e:	66                   	data16
   f:	2e                   	cs
  10:	0f                   	.byte 0xf
  11:	1f                   	(bad)
  12:	84 00                	test   %al,(%rax)
	...
[  144.703224] RSP: 0018:ffffae7900063d70 EFLAGS: 00010286
[  144.703497] RAX: 0000000000000000 RBX: ffffffffb67472c0 RCX: 00000000ffffdfff
[  144.703884] RDX: 0000000000000000 RSI: 00000000ffffffea RDI: 0000000000000001
[  144.704275] RBP: 0000000000000000 R08: ffffffffb6f78508 R09: 00000000ffffdfff
[  144.704651] R10: ffffffffb6e98520 R11: ffffffffb6f48520 R12: ffff895981d06610
[  144.705009] R13: ffffae7900063e08 R14: ffff895981d06b80 R15: ffff895984322e50
[  144.705387] FS:  0000000000000000(0000) GS:ffff8959bec80000(0000) knlGS:0000000000000000
[  144.705827] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  144.706143] CR2: 0000558b47a42dec CR3: 000000000501a002 CR4: 0000000000770ef0
[  144.706582] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  144.707107] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  144.707633] PKRU: 55555554
[  144.707779] Call Trace:
[  144.707911]  <TASK>
[  144.708040] ? __warn (kernel/panic.c:677) 
[  144.708229] ? sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
[  144.708475] ? report_bug (lib/bug.c:201 lib/bug.c:219) 
[  144.708706] ? handle_bug (arch/x86/kernel/traps.c:238) 
[  144.708928] ? exc_invalid_op (arch/x86/kernel/traps.c:259 (discriminator 1)) 
[  144.709135] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:568) 
[  144.709368] ? sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
[  144.709602] br_dev_delete (net/bridge/br_if.c:396) 
[  144.709804] br_net_exit_batch_rtnl (net/bridge/br.c:369) 
[  144.710078] cleanup_net (net/core/net_namespace.c:630) 
[  144.710267] ? process_one_work (kernel/workqueue.c:2606) 
[  144.710504] process_one_work (kernel/workqueue.c:2633) 
[  144.710717] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[  144.710917] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[  144.711177] kthread (kernel/kthread.c:388) 
[  144.711347] ? __pfx_kthread (kernel/kthread.c:341) 
[  144.711552] ret_from_fork (arch/x86/kernel/process.c:147) 
[  144.711743] ? __pfx_kthread (kernel/kthread.c:341) 
[  144.711944] ret_from_fork_asm (arch/x86/entry/entry_64.S:250) 
| [  156.999783] ------------[ cut here ]------------
| [  157.000188] sysfs group 'bridge' not found for kobject 'br0'
| [  157.000692] WARNING: CPU: 0 PID: 11 at fs/sysfs/group.c:282 sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
| [  157.001322] Modules linked in:
[  157.002272] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  157.003184] Workqueue: netns cleanup_net
[  157.003528] RIP: 0010:sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
[ 157.003906] Code: 48 89 ef 5d 41 5c e9 7a ad ff ff 48 89 ef e8 12 9b ff ff eb d1 90 49 8b 14 24 48 8b 33 48 c7 c7 d0 cd b2 b6 e8 ac 67 c5 ff 90 <0f> 0b 90 90 5b 5d 41 5c c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00
All code
========
   0:	48 89 ef             	mov    %rbp,%rdi
   3:	5d                   	pop    %rbp
   4:	41 5c                	pop    %r12
   6:	e9 7a ad ff ff       	jmp    0xffffffffffffad85
   b:	48 89 ef             	mov    %rbp,%rdi
   e:	e8 12 9b ff ff       	call   0xffffffffffff9b25
  13:	eb d1                	jmp    0xffffffffffffffe6
  15:	90                   	nop
  16:	49 8b 14 24          	mov    (%r12),%rdx
  1a:	48 8b 33             	mov    (%rbx),%rsi
  1d:	48 c7 c7 d0 cd b2 b6 	mov    $0xffffffffb6b2cdd0,%rdi
  24:	e8 ac 67 c5 ff       	call   0xffffffffffc567d5
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	5b                   	pop    %rbx
  2f:	5d                   	pop    %rbp
  30:	41 5c                	pop    %r12
  32:	c3                   	ret
  33:	cc                   	int3
  34:	cc                   	int3
  35:	cc                   	int3
  36:	cc                   	int3
  37:	66                   	data16
  38:	66                   	data16
  39:	2e                   	cs
  3a:	0f                   	.byte 0xf
  3b:	1f                   	(bad)
  3c:	84 00                	test   %al,(%rax)
	...

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	90                   	nop
   4:	5b                   	pop    %rbx
   5:	5d                   	pop    %rbp
   6:	41 5c                	pop    %r12
   8:	c3                   	ret
   9:	cc                   	int3
   a:	cc                   	int3
   b:	cc                   	int3
   c:	cc                   	int3
   d:	66                   	data16
   e:	66                   	data16
   f:	2e                   	cs
  10:	0f                   	.byte 0xf
  11:	1f                   	(bad)
  12:	84 00                	test   %al,(%rax)
	...
[  157.005309] RSP: 0018:ffffae7900063d70 EFLAGS: 00010286
[  157.005750] RAX: 0000000000000000 RBX: ffffffffb67472c0 RCX: 00000000ffffdfff
[  157.006310] RDX: 0000000000000000 RSI: 00000000ffffffea RDI: 0000000000000001
[  157.006878] RBP: 0000000000000000 R08: ffffffffb6f78508 R09: 00000000ffffdfff
[  157.007457] R10: ffffffffb6e98520 R11: ffffffffb6f48520 R12: ffff895984268610
[  157.008038] R13: ffffae7900063e08 R14: ffff895984268b80 R15: ffff895984320050
[  157.008620] FS:  0000000000000000(0000) GS:ffff8959bec00000(0000) knlGS:0000000000000000
[  157.009243] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  157.009721] CR2: 0000558b47a42dec CR3: 000000000501a006 CR4: 0000000000770ef0
[  157.010290] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  157.010857] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  157.011408] PKRU: 55555554
[  157.011662] Call Trace:
[  157.011885]  <TASK>
[  157.012079] ? __warn (kernel/panic.c:677) 
[  157.012349] ? sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
[  157.012711] ? report_bug (lib/bug.c:201 lib/bug.c:219) 
[  157.013032] ? handle_bug (arch/x86/kernel/traps.c:238) 
[  157.013331] ? exc_invalid_op (arch/x86/kernel/traps.c:259 (discriminator 1)) 
[  157.013651] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:568) 
[  157.014015] ? sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
[  157.014370] br_dev_delete (net/bridge/br_if.c:396) 
[  157.014686] br_net_exit_batch_rtnl (net/bridge/br.c:369) 
[  157.015039] cleanup_net (net/core/net_namespace.c:630) 
[  157.015350] ? process_one_work (kernel/workqueue.c:2606) 
[  157.015715] process_one_work (kernel/workqueue.c:2633) 
[  157.016059] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[  157.016386] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[  157.016756] kthread (kernel/kthread.c:388) 
[  157.017033] ? __pfx_kthread (kernel/kthread.c:341) 
[  157.017346] ret_from_fork (arch/x86/kernel/process.c:147) 
[  157.017667] ? __pfx_kthread (kernel/kthread.c:341) 
[  157.018002] ret_from_fork_asm (arch/x86/entry/entry_64.S:250) 
| [  169.529591] ------------[ cut here ]------------
| [  169.529967] sysfs group 'bridge' not found for kobject 'br0'
| [  169.530284] WARNING: CPU: 0 PID: 11 at fs/sysfs/group.c:282 sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
| [  169.530716] Modules linked in:
[  169.531315] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  169.531983] Workqueue: netns cleanup_net
[  169.532292] RIP: 0010:sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
[ 169.532739] Code: 48 89 ef 5d 41 5c e9 7a ad ff ff 48 89 ef e8 12 9b ff ff eb d1 90 49 8b 14 24 48 8b 33 48 c7 c7 d0 cd b2 b6 e8 ac 67 c5 ff 90 <0f> 0b 90 90 5b 5d 41 5c c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00
All code
========
   0:	48 89 ef             	mov    %rbp,%rdi
   3:	5d                   	pop    %rbp
   4:	41 5c                	pop    %r12
   6:	e9 7a ad ff ff       	jmp    0xffffffffffffad85
   b:	48 89 ef             	mov    %rbp,%rdi
   e:	e8 12 9b ff ff       	call   0xffffffffffff9b25
  13:	eb d1                	jmp    0xffffffffffffffe6
  15:	90                   	nop
  16:	49 8b 14 24          	mov    (%r12),%rdx
  1a:	48 8b 33             	mov    (%rbx),%rsi
  1d:	48 c7 c7 d0 cd b2 b6 	mov    $0xffffffffb6b2cdd0,%rdi
  24:	e8 ac 67 c5 ff       	call   0xffffffffffc567d5
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	5b                   	pop    %rbx
  2f:	5d                   	pop    %rbp
  30:	41 5c                	pop    %r12
  32:	c3                   	ret
  33:	cc                   	int3
  34:	cc                   	int3
  35:	cc                   	int3
  36:	cc                   	int3
  37:	66                   	data16
  38:	66                   	data16
  39:	2e                   	cs
  3a:	0f                   	.byte 0xf
  3b:	1f                   	(bad)
  3c:	84 00                	test   %al,(%rax)
	...

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	90                   	nop
   4:	5b                   	pop    %rbx
   5:	5d                   	pop    %rbp
   6:	41 5c                	pop    %r12
   8:	c3                   	ret
   9:	cc                   	int3
   a:	cc                   	int3
   b:	cc                   	int3
   c:	cc                   	int3
   d:	66                   	data16
   e:	66                   	data16
   f:	2e                   	cs
  10:	0f                   	.byte 0xf
  11:	1f                   	(bad)
  12:	84 00                	test   %al,(%rax)
	...
[  169.534215] RSP: 0018:ffffae7900063d70 EFLAGS: 00010286
[  169.534684] RAX: 0000000000000000 RBX: ffffffffb67472c0 RCX: 00000000ffffdfff
[  169.535287] RDX: 0000000000000000 RSI: 00000000ffffffea RDI: 0000000000000001
[  169.535730] RBP: 0000000000000000 R08: ffffffffb6f78508 R09: 00000000ffffdfff
[  169.536142] R10: ffffffffb6e98520 R11: ffffffffb6f48520 R12: ffff895981d06610
[  169.536571] R13: ffffae7900063e08 R14: ffff895981d06b80 R15: ffff8959842b4550
[  169.536973] FS:  0000000000000000(0000) GS:ffff8959bec00000(0000) knlGS:0000000000000000
[  169.537434] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  169.537761] CR2: 00007f1b56715000 CR3: 000000003ba60002 CR4: 0000000000770ef0
[  169.538195] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  169.538764] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  169.539346] PKRU: 55555554
[  169.539608] Call Trace:
[  169.539837]  <TASK>
[  169.540048] ? __warn (kernel/panic.c:677) 
[  169.540344] ? sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
[  169.540683] ? report_bug (lib/bug.c:201 lib/bug.c:219) 
[  169.540979] ? handle_bug (arch/x86/kernel/traps.c:238) 
[  169.541250] ? exc_invalid_op (arch/x86/kernel/traps.c:259 (discriminator 1)) 
[  169.541630] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:568) 
[  169.542038] ? sysfs_remove_group (fs/sysfs/group.c:282 (discriminator 1)) 
[  169.542391] br_dev_delete (net/bridge/br_if.c:396) 
[  169.542740] br_net_exit_batch_rtnl (net/bridge/br.c:369) 
[  169.543135] cleanup_net (net/core/net_namespace.c:630) 
[  169.543497] ? process_one_work (kernel/workqueue.c:2606) 
[  169.543881] process_one_work (kernel/workqueue.c:2633) 
[  169.544234] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[  169.544567] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[  169.544941] kthread (kernel/kthread.c:388) 
[  169.545288] ? __pfx_kthread (kernel/kthread.c:341) 
[  169.545634] ret_from_fork (arch/x86/kernel/process.c:147) 
[  169.545942] ? __pfx_kthread (kernel/kthread.c:341) 


Finger prints:
refcount_warn_saturate:br_sysfs_delbr:br_dev_delete:br_net_exit_batch_rtnl
sysfs_remove_group:br_dev_delete:br_net_exit_batch_rtnl:cleanup_net
sysfs_remove_group:br_dev_delete:br_net_exit_batch_rtnl:cleanup_net
sysfs_remove_group:br_dev_delete:br_net_exit_batch_rtnl:cleanup_net
sysfs_remove_group:br_dev_delete:br_net_exit_batch_rtnl:cleanup_net