======================================
| [   17.254564][  T231] ==================================================================
| [   17.255004][  T231] BUG: KASAN: null-ptr-deref in try_to_grab_pending (./arch/x86/include/asm/bitops.h:136 ./include/asm-generic/bitops/instrumented-atomic.h:72 kernel/workqueue.c:2072)
| [   17.255399][  T231] Write of size 8 at addr 0000000000000000 by task packetdrill/231
| [   17.255821][  T231]
[   17.255963][  T231] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   17.255965][  T231] Call Trace:
[   17.255968][  T231]  <TASK>
[   17.255971][  T231]  dump_stack_lvl (lib/dump_stack.c:123)
[   17.255981][  T231]  ? try_to_grab_pending (./arch/x86/include/asm/bitops.h:136 ./include/asm-generic/bitops/instrumented-atomic.h:72 kernel/workqueue.c:2072)
[   17.255987][  T231]  kasan_report (mm/kasan/report.c:597)
[   17.255996][  T231]  ? try_to_grab_pending (./arch/x86/include/asm/bitops.h:136 ./include/asm-generic/bitops/instrumented-atomic.h:72 kernel/workqueue.c:2072)
[   17.256005][  T231]  kasan_check_range (mm/kasan/generic.c:194 mm/kasan/generic.c:200)
[   17.256013][  T231]  try_to_grab_pending (./arch/x86/include/asm/bitops.h:136 ./include/asm-generic/bitops/instrumented-atomic.h:72 kernel/workqueue.c:2072)
[   17.256020][  T231]  __cancel_work (kernel/workqueue.c:2161 kernel/workqueue.c:4364)
[   17.256026][  T231]  ? enable_delayed_work (kernel/workqueue.c:4359)
[   17.256033][  T231]  ? qdisc_destroy (net/sched/sch_generic.c:1355)
[   17.256042][  T231]  __cancel_work_sync (kernel/workqueue.c:4383)
[   17.256049][  T231]  __dev_close_many (net/core/dev.c:1879 (discriminator 2) net/core/dev.c:1932 (discriminator 2))
[   17.256056][  T231]  ? netdev_notify_peers (net/core/dev.c:1891)
[   17.256062][  T231]  ? netif_close_many (net/core/dev.c:1959)
[   17.256068][  T231]  netif_close_many (net/core/dev.c:1959)
[   17.256073][  T231]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   17.256082][  T231]  ? __dev_close_many (net/core/dev.c:1949)
[   17.256087][  T231]  ? netif_close_many_and_unlock (net/core/dev.c:12476)
[   17.256094][  T231]  unregister_netdevice_many_notify (net/core/dev.c:12545)
[   17.256103][  T231]  ? sched_ttwu_pending (kernel/sched/core.c:4144)
[   17.256110][  T231]  ? dev_ingress_queue_create (net/core/dev.c:12499)
[   17.256118][  T231]  ? irqentry_exit (kernel/entry/common.c:215)
[   17.256124][  T231]  ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4472)
[   17.256131][  T231]  unregister_netdevice_queue (net/core/dev.c:12452)
[   17.256137][  T231]  ? unregister_netdevice_many (net/core/dev.c:12441)
[   17.256144][  T231]  ? queue_delayed_work_on (kernel/workqueue.c:2567)
[   17.256151][  T231]  __tun_detach (./include/linux/netdevice.h:3491 drivers/net/tun.c:621)
[   17.256162][  T231]  tun_chr_close (drivers/net/tun.c:638 drivers/net/tun.c:3436)
[   17.256168][  T231]  __fput (fs/file_table.c:468)
[   17.256179][  T231]  fput_close_sync (fs/file_table.c:571)
[   17.256184][  T231]  ? alloc_file_clone (fs/file_table.c:571)
[   17.256191][  T231]  __x64_sys_close (fs/open.c:1592 fs/open.c:1574 fs/open.c:1574)
[   17.256197][  T231]  do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
[   17.256206][  T231]  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   17.256212][  T231] RIP: 0033:0x4901eb
[   17.256218][  T231] Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 c3 78 04 00 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 21 79 04 00 8b 44
All code
========
   0:	03 00                	add    (%rax),%eax
   2:	00 00                	add    %al,(%rax)
   4:	0f 05                	syscall
   6:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   c:	77 41                	ja     0x4f
   e:	c3                   	ret
   f:	48 83 ec 18          	sub    $0x18,%rsp
  13:	89 7c 24 0c          	mov    %edi,0xc(%rsp)
  17:	e8 c3 78 04 00       	call   0x478df
  1c:	8b 7c 24 0c          	mov    0xc(%rsp),%edi
  20:	41 89 c0             	mov    %eax,%r8d
  23:	b8 03 00 00 00       	mov    $0x3,%eax
  28:	0f 05                	syscall
  2a:*	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax		<-- trapping instruction
  30:	77 35                	ja     0x67
  32:	44 89 c7             	mov    %r8d,%edi
  35:	89 44 24 0c          	mov    %eax,0xc(%rsp)
  39:	e8 21 79 04 00       	call   0x4795f
  3e:	8b                   	.byte 0x8b
  3f:	44                   	rex.R

Code starting with the faulting instruction
===========================================
   0:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   6:	77 35                	ja     0x3d
   8:	44 89 c7             	mov    %r8d,%edi
   b:	89 44 24 0c          	mov    %eax,0xc(%rsp)
   f:	e8 21 79 04 00       	call   0x47935
  14:	8b                   	.byte 0x8b
  15:	44                   	rex.R
[   17.256222][  T231] RSP: 002b:00007fff22d13900 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
[   17.256227][  T231] RAX: ffffffffffffffda RBX: 00007fff22d13e60 RCX: 00000000004901eb
[   17.256231][  T231] RDX: 0000000000000002 RSI: 0000000000000002 RDI: 0000000000000005
[   17.256233][  T231] RBP: 00007fff22d13940 R08: 0000000000000000 R09: 0000000000000000
[   17.256236][  T231] R10: 0000000015b33f50 R11: 0000000000000293 R12: 00007fff22d13dd8
[   17.256238][  T231] R13: 0000000000000001 R14: 000000000054e030 R15: 0000000000000001
| [   17.270840][  T231] #PF: error_code(0x0002) - not-present page
| [   17.271157][  T231] PGD c321067 P4D c321067 PUD bd57067 PMD 0
| [   17.271490][  T231] Oops: Oops: 0002 [#1] SMP KASAN
| [   17.272328][  T231] Tainted: [B]=BAD_PAGE
[   17.272524][  T231] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   17.272846][  T231] RIP: 0010:try_to_grab_pending (./arch/x86/include/asm/bitops.h:136 ./include/asm-generic/bitops/instrumented-atomic.h:72 kernel/workqueue.c:2072)
[   17.273185][  T231] Code: 00 41 89 c0 b8 01 00 00 00 45 85 c0 74 0f 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 be 08 00 00 00 48 89 df e8 7f 7f 81 00 <f0> 48 0f ba 2b 00 72 11 48 83 c4 10 31 c0 5b 5d 41 5c 41 5d 41 5e
All code
========
   0:	00 41 89             	add    %al,-0x77(%rcx)
   3:	c0 b8 01 00 00 00 45 	sarb   $0x45,0x1(%rax)
   a:	85 c0                	test   %eax,%eax
   c:	74 0f                	je     0x1d
   e:	48 83 c4 10          	add    $0x10,%rsp
  12:	5b                   	pop    %rbx
  13:	5d                   	pop    %rbp
  14:	41 5c                	pop    %r12
  16:	41 5d                	pop    %r13
  18:	41 5e                	pop    %r14
  1a:	41 5f                	pop    %r15
  1c:	c3                   	ret
  1d:	be 08 00 00 00       	mov    $0x8,%esi
  22:	48 89 df             	mov    %rbx,%rdi
  25:	e8 7f 7f 81 00       	call   0x817fa9
  2a:*	f0 48 0f ba 2b 00    	lock btsq $0x0,(%rbx)		<-- trapping instruction
  30:	72 11                	jb     0x43
  32:	48 83 c4 10          	add    $0x10,%rsp
  36:	31 c0                	xor    %eax,%eax
  38:	5b                   	pop    %rbx
  39:	5d                   	pop    %rbp
  3a:	41 5c                	pop    %r12
  3c:	41 5d                	pop    %r13
  3e:	41 5e                	pop    %r14

Code starting with the faulting instruction
===========================================
   0:	f0 48 0f ba 2b 00    	lock btsq $0x0,(%rbx)
   6:	72 11                	jb     0x19
   8:	48 83 c4 10          	add    $0x10,%rsp
   c:	31 c0                	xor    %eax,%eax
   e:	5b                   	pop    %rbx
   f:	5d                   	pop    %rbp
  10:	41 5c                	pop    %r12
  12:	41 5d                	pop    %r13
  14:	41 5e                	pop    %r14
[   17.274081][  T231] RSP: 0018:ffffc90000ad7900 EFLAGS: 00010046
[   17.274417][  T231] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8dc3e90a
[   17.274797][  T231] RDX: fffffbfff23ca0cd RSI: 0000000000000008 RDI: ffffffff91e50660
[   17.275171][  T231] RBP: ffffc90000ad7968 R08: 0000000000000001 R09: fffffbfff23ca0cc
[   17.275544][  T231] R10: ffffffff91e50667 R11: ffffc90000ad73c0 R12: 0000000000000000
[   17.275926][  T231] R13: 0000000000000286 R14: ffff888008c68000 R15: dffffc0000000000
[   17.276307][  T231] FS:  0000000015b2c3c0(0000) GS:ffff8880a459b000(0000) knlGS:0000000000000000
[   17.276756][  T231] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   17.277088][  T231] CR2: 0000000000000000 CR3: 00000000088e0002 CR4: 0000000000772ef0
[   17.277478][  T231] PKRU: 55555554
[   17.277692][  T231] Call Trace:
[   17.277884][  T231]  <TASK>
[   17.278021][  T231]  __cancel_work (kernel/workqueue.c:2161 kernel/workqueue.c:4364)
[   17.278290][  T231]  ? enable_delayed_work (kernel/workqueue.c:4359)
[   17.278558][  T231]  ? qdisc_destroy (net/sched/sch_generic.c:1355)
[   17.278819][  T231]  __cancel_work_sync (kernel/workqueue.c:4383)
[   17.279113][  T231]  __dev_close_many (net/core/dev.c:1879 (discriminator 2) net/core/dev.c:1932 (discriminator 2))
[   17.279391][  T231]  ? netdev_notify_peers (net/core/dev.c:1891)
[   17.279653][  T231]  ? netif_close_many (net/core/dev.c:1959)
[   17.279915][  T231]  netif_close_many (net/core/dev.c:1959)
[   17.280172][  T231]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   17.280436][  T231]  ? __dev_close_many (net/core/dev.c:1949)
[   17.280691][  T231]  ? netif_close_many_and_unlock (net/core/dev.c:12476)
[   17.281013][  T231]  unregister_netdevice_many_notify (net/core/dev.c:12545)
[   17.281342][  T231]  ? sched_ttwu_pending (kernel/sched/core.c:4144)
[   17.281605][  T231]  ? dev_ingress_queue_create (net/core/dev.c:12499)
[   17.281864][  T231]  ? irqentry_exit (kernel/entry/common.c:215)
[   17.282124][  T231]  ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4472)
[   17.282385][  T231]  unregister_netdevice_queue (net/core/dev.c:12452)
[   17.282644][  T231]  ? unregister_netdevice_many (net/core/dev.c:12441)
[   17.282898][  T231]  ? queue_delayed_work_on (kernel/workqueue.c:2567)
[   17.283154][  T231]  __tun_detach (./include/linux/netdevice.h:3491 drivers/net/tun.c:621)
[   17.283422][  T231]  tun_chr_close (drivers/net/tun.c:638 drivers/net/tun.c:3436)
[   17.283677][  T231]  __fput (fs/file_table.c:468)
[   17.283877][  T231]  fput_close_sync (fs/file_table.c:571)
[   17.284133][  T231]  ? alloc_file_clone (fs/file_table.c:571)
[   17.284391][  T231]  __x64_sys_close (fs/open.c:1592 fs/open.c:1574 fs/open.c:1574)
[   17.284646][  T231]  do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
[   17.284905][  T231]  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   17.285214][  T231] RIP: 0033:0x4901eb
[   17.285415][  T231] Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 c3 78 04 00 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 21 79 04 00 8b 44
All code
========
   0:	03 00                	add    (%rax),%eax
   2:	00 00                	add    %al,(%rax)
   4:	0f 05                	syscall
   6:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   c:	77 41                	ja     0x4f
   e:	c3                   	ret
   f:	48 83 ec 18          	sub    $0x18,%rsp
  13:	89 7c 24 0c          	mov    %edi,0xc(%rsp)
  17:	e8 c3 78 04 00       	call   0x478df
  1c:	8b 7c 24 0c          	mov    0xc(%rsp),%edi
  20:	41 89 c0             	mov    %eax,%r8d
  23:	b8 03 00 00 00       	mov    $0x3,%eax
  28:	0f 05                	syscall
  2a:*	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax		<-- trapping instruction
  30:	77 35                	ja     0x67
  32:	44 89 c7             	mov    %r8d,%edi
  35:	89 44 24 0c          	mov    %eax,0xc(%rsp)
  39:	e8 21 79 04 00       	call   0x4795f
  3e:	8b                   	.byte 0x8b
  3f:	44                   	rex.R

Code starting with the faulting instruction
===========================================
   0:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   6:	77 35                	ja     0x3d
   8:	44 89 c7             	mov    %r8d,%edi
   b:	89 44 24 0c          	mov    %eax,0xc(%rsp)
   f:	e8 21 79 04 00       	call   0x47935
  14:	8b                   	.byte 0x8b
  15:	44                   	rex.R
[   17.286332][  T231] RSP: 002b:00007fff22d13900 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
[   17.286712][  T231] RAX: ffffffffffffffda RBX: 00007fff22d13e60 RCX: 00000000004901eb
[   17.287085][  T231] RDX: 0000000000000002 RSI: 0000000000000002 RDI: 0000000000000005
[   17.287461][  T231] RBP: 00007fff22d13940 R08: 0000000000000000 R09: 0000000000000000
[   17.287850][  T231] R10: 0000000015b33f50 R11: 0000000000000293 R12: 00007fff22d13dd8


Finger prints:
kasan_report:kasan_check_range:try_to_grab_pending:__cancel_work:__cancel_work_sync
try_to_grab_pending:__cancel_work:__cancel_work_sync:__dev_close_many:netif_close_many