net.ipv6.conf.syz0.accept_dad = 0
net.ipv6.conf.syz0.router_solicitations = 0
executing program
syzkaller login: [   22.684732] ==================================================================
[   22.685604] BUG: KASAN: use-after-free in detach_if_pending+0x557/0x610
[   22.686327] Write of size 8 at addr ffff88003bc336c0 by task syzkaller455543/2974
[   22.687150] 
[   22.687344] CPU: 0 PID: 2974 Comm: syzkaller455543 Not tainted 4.13.0-next-20170911+ #1
[   22.688234] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
[   22.689144] Call Trace:
[   22.689446]  dump_stack+0x194/0x257
[   22.689858]  ? arch_local_irq_restore+0x53/0x53
[   22.690392]  ? show_regs_print_info+0x65/0x65
[   22.690891]  ? lock_timer_base+0x1a3/0x2b0
[   22.691372]  ? detach_if_pending+0x557/0x610
[   22.691857]  print_address_description+0x73/0x250
[   22.700219]  ? detach_if_pending+0x557/0x610
[   22.700625]  kasan_report+0x24e/0x340
[   22.702020]  __asan_report_store8_noabort+0x17/0x20
[   22.702539]  detach_if_pending+0x557/0x610
[   22.704031]  ? trace_raw_output_tick_stop+0x130/0x130
[   22.704570]  ? _raw_spin_lock_irqsave+0x9e/0xc0
[   22.706149]  ? lock_timer_base+0x1a3/0x2b0
[   22.706590]  ? lock_timer_base+0x1eb/0x2b0
[   22.708133]  ? __internal_add_timer+0x2d0/0x2d0
[   22.708620]  ? trace_hardirqs_on+0xd/0x10
[   22.709226]  try_to_del_timer_sync+0xa2/0x120
[   22.709663]  ? del_timer+0x130/0x130
[   22.710052]  ? del_timer_sync+0xeb/0x240
[   22.710458]  del_timer_sync+0x18a/0x240
[   22.710840]  tun_free_netdev+0x105/0x1b0
[   22.711257]  ? tun_xdp+0x410/0x410
[   22.711592]  ? cpumask_next+0x24/0x30
[   22.711958]  ? netdev_refcnt_read+0xed/0x150
[   22.712407]  ? tun_xdp+0x410/0x410
[   22.712741]  netdev_run_todo+0x870/0xca0
[   22.713104]  ? do_group_exit+0x149/0x400
[   22.715043]  ? register_netdev+0x30/0x30
[   22.715661]  ? lock_downgrade+0x990/0x990
[   22.717501]  ? trace_hardirqs_on+0xd/0x10
[   22.718108]  ? refcount_sub_and_test+0x115/0x1b0
[   22.719399]  ? refcount_inc+0x50/0x50
[   22.719928]  ? refcount_inc+0x50/0x50
[   22.720494]  ? sk_destruct+0x4c/0x80
[   22.721020]  ? __sk_free+0x5c/0x230
[   22.722233]  ? sk_free+0x2f/0x40
[   22.727238]  ? __tun_detach+0x176/0x1390
[   22.728684]  ? tun_attach+0xf90/0xf90
[   22.732637]  ? do_raw_spin_trylock+0x190/0x190
[   22.736223]  ? locks_remove_file+0x3fa/0x5a0
[   22.736995]  ? fcntl_setlk+0x10d0/0x10d0
[   22.737742]  ? __fsnotify_parent+0xb4/0x3a0
[   22.738575]  ? fsnotify+0x1af0/0x1af0
[   22.739297]  ? __tun_detach+0x1390/0x1390
[   22.739924]  ? __tun_detach+0x1390/0x1390
[   22.740327]  rtnl_unlock+0xe/0x10
[   22.740653]  tun_chr_close+0x49/0x60
[   22.741001]  __fput+0x333/0x7f0
[   22.741313]  ? fput+0x140/0x140
[   22.743196]  ? check_same_owner+0x320/0x320
[   22.743644]  ? _raw_spin_unlock_irq+0x27/0x70
[   22.744118]  ____fput+0x15/0x20
[   22.744462]  task_work_run+0x199/0x270
[   22.744867]  ? task_work_cancel+0x210/0x210
[   22.745314]  ? _raw_spin_unlock+0x22/0x30
[   22.745757]  ? switch_task_namespaces+0x87/0xc0
[   22.746250]  do_exit+0xa52/0x1b40
[   22.746611]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   22.747130]  ? check_noncircular+0x20/0x20
[   22.750806]  ? __handle_mm_fault+0x587/0x39c0
[   22.751731]  ? mm_update_next_owner+0x930/0x930
[   22.752591]  ? __pmd_alloc+0x4e0/0x4e0
[   22.753250]  ? find_held_lock+0x39/0x1d0
[   22.754012]  ? lock_downgrade+0x990/0x990
[   22.764738]  ? handle_mm_fault+0x410/0x8d0
[   22.765607]  ? down_read_trylock+0xdb/0x170
[   22.766430]  ? __do_page_fault+0x2b8/0xb60
[   22.767211]  ? __handle_mm_fault+0x39c0/0x39c0
[   22.768025]  ? vmacache_find+0x61/0x270
[   22.768744]  ? up_read+0x1a/0x40
[   22.769347]  ? __do_page_fault+0x35b/0xb60
[   22.770127]  ? do_page_fault+0xee/0x720
[   22.770829]  ? __do_page_fault+0xb60/0xb60
[   22.771345]  ? putname+0xf3/0x130
[   22.771724]  do_group_exit+0x149/0x400
[   22.772178]  ? lockdep_sys_exit+0x47/0xf0
[   22.772610]  ? SyS_exit+0x30/0x30
[   22.773047]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   22.773599]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[   22.774226]  SyS_exit_group+0x1d/0x20
[   22.774867]  entry_SYSCALL_64_fastpath+0x1f/0xbe
[   22.784359] RIP: 0033:0x438cd9
[   22.784846] RSP: 002b:00007ffeacfd6fd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
[   22.785724] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000438cd9
[   22.786586] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[   22.787443] RBP: 0000000000000082 R08: 000000000000003c R09: 00000000000000e7
[   22.788081] R10: ffffffffffffffcc R11: 0000000000000246 R12: 0000000000000001
[   22.788719] R13: 00000000006cc300 R14: 00000000004027d0 R15: 0000000000000000
[   22.789386] 
[   22.789534] Allocated by task 2974:
[   22.790000]  save_stack_trace+0x16/0x20
[   22.790625]  save_stack+0x43/0xd0
[   22.791144]  kasan_kmalloc+0xad/0xe0
[   22.791597]  __kmalloc_node+0x47/0x70
[   22.792025]  kvmalloc_node+0x64/0xd0
[   22.792662]  alloc_netdev_mqs+0x16e/0xed0
[   22.793401]  __tun_chr_ioctl+0x12be/0x3d20
[   22.794034]  tun_chr_ioctl+0x2a/0x40
[   22.794468]  do_vfs_ioctl+0x1b1/0x1530
[   22.794907]  SyS_ioctl+0x8f/0xc0
[   22.795371]  entry_SYSCALL_64_fastpath+0x1f/0xbe
[   22.795878] 
[   22.796099] Freed by task 2974:
[   22.796470]  save_stack_trace+0x16/0x20
[   22.796909]  save_stack+0x43/0xd0
[   22.797297]  kasan_slab_free+0x71/0xc0
[   22.797743]  kfree+0xca/0x250
[   22.798183]  kvfree+0x36/0x60
[   22.799762]  free_netdev+0x2cf/0x360
[   22.800994]  __tun_chr_ioctl+0x2cf6/0x3d20
[   22.801430]  tun_chr_ioctl+0x2a/0x40
[   22.801770]  do_vfs_ioctl+0x1b1/0x1530
[   22.802159]  SyS_ioctl+0x8f/0xc0
[   22.802570]  entry_SYSCALL_64_fastpath+0x1f/0xbe
[   22.802973] 
[   22.803093] The buggy address belongs to the object at ffff88003bc302c0
[   22.803093]  which belongs to the cache kmalloc-16384 of size 16384
[   22.804323] The buggy address is located 13312 bytes inside of
[   22.804323]  16384-byte region [ffff88003bc302c0, ffff88003bc342c0)
[   22.805575] The buggy address belongs to the page:
[   22.806210] page:ffffea0000ef0c00 count:1 mapcount:0 mapping:ffff88003bc302c0 index:0x0 compound_mapcount: 0
[   22.807965] flags: 0x100000000008100(slab|head)
[   22.808360] raw: 0100000000008100 ffff88003bc302c0 0000000000000000 0000000100000001
[   22.809373] raw: ffffea0000ecd020 ffff88003e801c50 ffff88003e802200 0000000000000000
[   22.810243] page dumped because: kasan: bad access detected
[   22.810802] 
[   22.810950] Memory state around the buggy address:
[   22.811602]  ffff88003bc33580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   22.812294]  ffff88003bc33600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   22.812965] >ffff88003bc33680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   22.813664]                                            ^
[   22.814197]  ffff88003bc33700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   22.814851]  ffff88003bc33780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   22.815525] ==================================================================
[   22.816202] Disabling lock debugging due to kernel taint
[   22.816708] Kernel panic - not syncing: panic_on_warn set ...
[   22.816708] 
[   22.817396] CPU: 0 PID: 2974 Comm: syzkaller455543 Tainted: G    B           4.13.0-next-20170911+ #1
[   22.818532] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
[   22.821233] Call Trace:
[   22.821702]  dump_stack+0x194/0x257
[   22.822371]  ? arch_local_irq_restore+0x53/0x53
[   22.822818]  ? vprintk_default+0x28/0x30
[   22.823188]  ? detach_if_pending+0x4c0/0x610
[   22.823641]  panic+0x1e4/0x417
[   22.823950]  ? __warn+0x1d9/0x1d9
[   22.824386]  ? detach_if_pending+0x557/0x610
[   22.824835]  kasan_end_report+0x50/0x50
[   22.825253]  kasan_report+0x137/0x340
[   22.825648]  __asan_report_store8_noabort+0x17/0x20
[   22.826311]  detach_if_pending+0x557/0x610
[   22.827081]  ? trace_raw_output_tick_stop+0x130/0x130
[   22.828042]  ? _raw_spin_lock_irqsave+0x9e/0xc0
[   22.828881]  ? lock_timer_base+0x1a3/0x2b0
[   22.829632]  ? lock_timer_base+0x1eb/0x2b0
[   22.830333]  ? __internal_add_timer+0x2d0/0x2d0
[   22.830813]  ? trace_hardirqs_on+0xd/0x10
[   22.831250]  try_to_del_timer_sync+0xa2/0x120
[   22.831711]  ? del_timer+0x130/0x130
[   22.832125]  ? del_timer_sync+0xeb/0x240
[   22.832530]  del_timer_sync+0x18a/0x240
[   22.832900]  tun_free_netdev+0x105/0x1b0
[   22.833345]  ? tun_xdp+0x410/0x410
[   22.833666]  ? cpumask_next+0x24/0x30
[   22.834037]  ? netdev_refcnt_read+0xed/0x150
[   22.834495]  ? tun_xdp+0x410/0x410
[   22.834818]  netdev_run_todo+0x870/0xca0
[   22.835371]  ? do_group_exit+0x149/0x400
[   22.835807]  ? register_netdev+0x30/0x30
[   22.836455]  ? lock_downgrade+0x990/0x990
[   22.836962]  ? trace_hardirqs_on+0xd/0x10
[   22.837419]  ? refcount_sub_and_test+0x115/0x1b0
[   22.837872]  ? refcount_inc+0x50/0x50
[   22.838536]  ? refcount_inc+0x50/0x50
[   22.839206]  ? sk_destruct+0x4c/0x80
[   22.839675]  ? __sk_free+0x5c/0x230
[   22.840302]  ? sk_free+0x2f/0x40
[   22.840862]  ? __tun_detach+0x176/0x1390
[   22.842897]  ? tun_attach+0xf90/0xf90
[   22.843578]  ? do_raw_spin_trylock+0x190/0x190
[   22.844437]  ? locks_remove_file+0x3fa/0x5a0
[   22.845261]  ? fcntl_setlk+0x10d0/0x10d0
[   22.846022]  ? __fsnotify_parent+0xb4/0x3a0
[   22.846724]  ? fsnotify+0x1af0/0x1af0
[   22.847266]  ? __tun_detach+0x1390/0x1390
[   22.847802]  ? __tun_detach+0x1390/0x1390
[   22.848574]  rtnl_unlock+0xe/0x10
[   22.849217]  tun_chr_close+0x49/0x60
[   22.849617]  __fput+0x333/0x7f0
[   22.849976]  ? fput+0x140/0x140
[   22.850371]  ? check_same_owner+0x320/0x320
[   22.850827]  ? _raw_spin_unlock_irq+0x27/0x70
[   22.851290]  ____fput+0x15/0x20
[   22.851632]  task_work_run+0x199/0x270
[   22.852037]  ? task_work_cancel+0x210/0x210
[   22.852770]  ? _raw_spin_unlock+0x22/0x30
[   22.853282]  ? switch_task_namespaces+0x87/0xc0
[   22.853801]  do_exit+0xa52/0x1b40
[   22.854122]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   22.854495]  ? check_noncircular+0x20/0x20
[   22.854882]  ? __handle_mm_fault+0x587/0x39c0
[   22.855320]  ? mm_update_next_owner+0x930/0x930
[   22.855790]  ? __pmd_alloc+0x4e0/0x4e0
[   22.856094]  ? find_held_lock+0x39/0x1d0
[   22.856469]  ? lock_downgrade+0x990/0x990
[   22.856867]  ? handle_mm_fault+0x410/0x8d0
[   22.857254]  ? down_read_trylock+0xdb/0x170
[   22.857664]  ? __do_page_fault+0x2b8/0xb60
[   22.858071]  ? __handle_mm_fault+0x39c0/0x39c0
[   22.858488]  ? vmacache_find+0x61/0x270
[   22.858851]  ? up_read+0x1a/0x40
[   22.859153]  ? __do_page_fault+0x35b/0xb60
[   22.859544]  ? do_page_fault+0xee/0x720
[   22.859913]  ? __do_page_fault+0xb60/0xb60
[   22.860313]  ? putname+0xf3/0x130
[   22.860640]  do_group_exit+0x149/0x400
[   22.861005]  ? lockdep_sys_exit+0x47/0xf0
[   22.861384]  ? SyS_exit+0x30/0x30
[   22.861702]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   22.862169]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[   22.862594]  SyS_exit_group+0x1d/0x20
[   22.864887]  entry_SYSCALL_64_fastpath+0x1f/0xbe
[   22.865420] RIP: 0033:0x438cd9
[   22.865718] RSP: 002b:00007ffeacfd6fd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
[   22.866491] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000438cd9
[   22.867200] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[   22.867912] RBP: 0000000000000082 R08: 000000000000003c R09: 00000000000000e7
[   22.870803] R10: ffffffffffffffcc R11: 0000000000000246 R12: 0000000000000001
[   22.872238] R13: 00000000006cc300 R14: 00000000004027d0 R15: 0000000000000000
[   22.873881] Dumping ftrace buffer:
[   22.874653]    (ftrace buffer empty)
[   22.875469] Kernel Offset: disabled
[   22.876261] Rebooting in 86400 seconds..