INIT: Entering runlevel: 2

[info] Using makefile-style concurrent boot in runlevel 2.
[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c.
[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c.
[....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c.

Debian GNU/Linux 7 syzkaller ttyS0

Warning: Permanently added 'ci-upstream-kasan-gce-386-2,10.128.15.201' (ECDSA) to the list of known hosts.
net.ipv6.conf.syz0.accept_dad = 0
net.ipv6.conf.syz0.router_solicitations = 0
executing program
syzkaller login: [   41.593488] ==================================================================
[   41.600961] BUG: KASAN: use-after-free in detach_if_pending+0x557/0x610
[   41.607692] Write of size 8 at addr ffff8801ce073780 by task syzkaller681867/2984
[   41.615281] 
[   41.616884] CPU: 1 PID: 2984 Comm: syzkaller681867 Not tainted 4.14.0-rc3+ #24
[   41.624218] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   41.633546] Call Trace:
[   41.636112]  dump_stack+0x194/0x257
[   41.639721]  ? arch_local_irq_restore+0x53/0x53
[   41.644371]  ? show_regs_print_info+0x65/0x65
[   41.648846]  ? lock_timer_base+0x1a3/0x2b0
[   41.653055]  ? detach_if_pending+0x557/0x610
[   41.657438]  print_address_description+0x73/0x250
[   41.662252]  ? detach_if_pending+0x557/0x610
[   41.666633]  kasan_report+0x25b/0x340
[   41.670410]  __asan_report_store8_noabort+0x17/0x20
[   41.675400]  detach_if_pending+0x557/0x610
[   41.679612]  ? trace_raw_output_tick_stop+0x130/0x130
[   41.684779]  ? _raw_spin_lock_irqsave+0x9e/0xc0
[   41.689422]  ? lock_timer_base+0x1a3/0x2b0
[   41.693637]  ? lock_timer_base+0x1eb/0x2b0
[   41.697850]  ? __internal_add_timer+0x2d0/0x2d0
[   41.702500]  ? trace_hardirqs_on+0xd/0x10
[   41.706632]  try_to_del_timer_sync+0xa2/0x120
[   41.711101]  ? del_timer+0x130/0x130
[   41.714791]  ? del_timer_sync+0xeb/0x240
[   41.718833]  del_timer_sync+0x18a/0x240
[   41.722787]  tun_free_netdev+0x105/0x1b0
[   41.726824]  ? tun_xdp+0x410/0x410
[   41.730337]  ? cpumask_next+0x24/0x30
[   41.734114]  ? netdev_refcnt_read+0xed/0x150
[   41.738499]  ? tun_xdp+0x410/0x410
[   41.742015]  netdev_run_todo+0x870/0xca0
[   41.746048]  ? do_group_exit+0x149/0x400
[   41.750086]  ? register_netdev+0x30/0x30
[   41.754124]  ? lock_downgrade+0x990/0x990
[   41.758244]  ? trace_hardirqs_on+0xd/0x10
[   41.762384]  ? refcount_sub_and_test+0x115/0x1b0
[   41.767112]  ? refcount_inc+0x50/0x50
[   41.770898]  ? refcount_inc+0x50/0x50
[   41.774677]  ? sk_destruct+0x4c/0x80
[   41.778362]  ? __sk_free+0x5c/0x230
[   41.781962]  ? sk_free+0x2f/0x40
[   41.785299]  ? __tun_detach+0x176/0x1390
[   41.789344]  ? tun_attach+0xf90/0xf90
[   41.793130]  ? locks_remove_file+0x3fa/0x5a0
[   41.797516]  ? fcntl_setlk+0x10d0/0x10d0
[   41.801557]  ? __fsnotify_parent+0xb4/0x3a0
[   41.805866]  ? fsnotify+0x1af0/0x1af0
[   41.809645]  ? __tun_detach+0x1390/0x1390
[   41.813769]  ? __tun_detach+0x1390/0x1390
[   41.817892]  rtnl_unlock+0xe/0x10
[   41.821316]  tun_chr_close+0x49/0x60
[   41.825007]  __fput+0x333/0x7f0
[   41.828266]  ? fput+0x140/0x140
[   41.831521]  ? check_same_owner+0x320/0x320
[   41.835823]  ____fput+0x15/0x20
[   41.839076]  task_work_run+0x199/0x270
[   41.842941]  ? task_work_cancel+0x210/0x210
[   41.847238]  ? free_nsproxy+0x185/0x1f0
[   41.851189]  ? switch_task_namespaces+0xa2/0xc0
[   41.855841]  do_exit+0x9d2/0x1af0
[   41.859266]  ? trace_hardirqs_on+0xd/0x10
[   41.863411]  ? mm_update_next_owner+0x930/0x930
[   41.868061]  ? mark_held_locks+0xb2/0x100
[   41.872189]  ? kfree+0xe4/0x250
[   41.875447]  ? kvfree+0x36/0x60
[   41.878701]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   41.883701]  ? trace_hardirqs_on+0xd/0x10
[   41.887829]  ? kvfree+0x3b/0x60
[   41.891091]  ? rtnl_unlock+0xe/0x10
[   41.894694]  ? __tun_chr_ioctl+0x27a/0x3d20
[   41.899008]  ? find_held_lock+0x39/0x1d0
[   41.903051]  ? __might_sleep+0x95/0x190
[   41.907011]  ? selinux_file_ioctl+0x444/0x690
[   41.911479]  ? __fget_light+0x29d/0x390
[   41.915445]  ? handle_mm_fault+0x410/0x8d0
[   41.919660]  ? tun_chr_compat_ioctl+0x29/0x30
[   41.924126]  ? tun_chr_compat_ioctl+0x29/0x30
[   41.928598]  do_group_exit+0x149/0x400
[   41.932456]  ? __tun_chr_ioctl+0x3d20/0x3d20
[   41.936837]  ? SyS_exit+0x30/0x30
[   41.940265]  ? do_ioctl+0x60/0x60
[   41.943696]  ? do_fast_syscall_32+0x158/0xf05
[   41.948168]  ? do_group_exit+0x400/0x400
[   41.952201]  SyS_exit_group+0x1d/0x20
[   41.955975]  do_fast_syscall_32+0x3f2/0xf05
[   41.960274]  ? do_int80_syscall_32+0x940/0x940
[   41.964829]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[   41.969562]  ? lockdep_sys_exit+0x47/0xf0
[   41.973683]  ? syscall_return_slowpath+0x2b3/0x510
[   41.978590]  ? sysret32_from_system_call+0x5/0x3b
[   41.983407]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   41.988227]  entry_SYSENTER_compat+0x51/0x60
[   41.992609] RIP: 0023:0xf7f1ac79
[   41.995944] RSP: 002b:00000000ff99d20c EFLAGS: 00000282 ORIG_RAX: 00000000000000fc
[   42.003627] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00000000ff99d3f8
[   42.010870] RDX: 0000000008048c9a RSI: 0000000000000036 RDI: 0000000000000004
[   42.018113] RBP: 00000000400454ca R08: 0000000000000000 R09: 0000000000000000
[   42.025354] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[   42.032600] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[   42.039863] 
[   42.041464] Allocated by task 2984:
[   42.045093]  save_stack_trace+0x16/0x20
[   42.049042]  save_stack+0x43/0xd0
[   42.052467]  kasan_kmalloc+0xad/0xe0
[   42.056152]  __kmalloc_node+0x47/0x70
[   42.059927]  kvmalloc_node+0x64/0xd0
[   42.063617]  alloc_netdev_mqs+0x16e/0xed0
[   42.067738]  __tun_chr_ioctl+0x12be/0x3d20
[   42.071942]  tun_chr_compat_ioctl+0x29/0x30
[   42.076236]  compat_SyS_ioctl+0x1d7/0x3290
[   42.080442]  do_fast_syscall_32+0x3f2/0xf05
[   42.084735]  entry_SYSENTER_compat+0x51/0x60
[   42.089113] 
[   42.090714] Freed by task 2984:
[   42.093965]  save_stack_trace+0x16/0x20
[   42.097912]  save_stack+0x43/0xd0
[   42.101335]  kasan_slab_free+0x71/0xc0
[   42.105205]  kfree+0xca/0x250
[   42.108284]  kvfree+0x36/0x60
[   42.111360]  free_netdev+0x2cf/0x360
[   42.115043]  __tun_chr_ioctl+0x2cf6/0x3d20
[   42.119246]  tun_chr_compat_ioctl+0x29/0x30
[   42.123538]  compat_SyS_ioctl+0x1d7/0x3290
[   42.127742]  do_fast_syscall_32+0x3f2/0xf05
[   42.132033]  entry_SYSENTER_compat+0x51/0x60
[   42.136406] 
[   42.138007] The buggy address belongs to the object at ffff8801ce070380
[   42.138007]  which belongs to the cache kmalloc-16384 of size 16384
[   42.150981] The buggy address is located 13312 bytes inside of
[   42.150981]  16384-byte region [ffff8801ce070380, ffff8801ce074380)
[   42.163173] The buggy address belongs to the page:
[   42.168073] page:ffffea0007381c00 count:1 mapcount:0 mapping:ffff8801ce070380 index:0x0 compound_mapcount: 0
[   42.178021] flags: 0x200000000008100(slab|head)
[   42.182665] raw: 0200000000008100 ffff8801ce070380 0000000000000000 0000000100000001
[   42.190518] raw: ffffea0007334a20 ffff8801dac01c50 ffff8801dac02200 0000000000000000
[   42.198367] page dumped because: kasan: bad access detected
[   42.204050] 
[   42.205651] Memory state around the buggy address:
[   42.210554]  ffff8801ce073680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   42.217882]  ffff8801ce073700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   42.225211] >ffff8801ce073780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   42.232555]                    ^
[   42.235897]  ffff8801ce073800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   42.243228]  ffff8801ce073880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   42.250561] ==================================================================
[   42.257888] Disabling lock debugging due to kernel taint
[   42.263304] Kernel panic - not syncing: panic_on_warn set ...
[   42.263304] 
[   42.270633] CPU: 1 PID: 2984 Comm: syzkaller681867 Tainted: G    B           4.14.0-rc3+ #24
[   42.279172] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   42.288492] Call Trace:
[   42.291057]  dump_stack+0x194/0x257
[   42.294653]  ? arch_local_irq_restore+0x53/0x53
[   42.299291]  ? vprintk_default+0x28/0x30
[   42.303322]  ? detach_if_pending+0x500/0x610
[   42.307702]  panic+0x1e4/0x417
[   42.310862]  ? __warn+0x1d9/0x1d9
[   42.314289]  ? detach_if_pending+0x557/0x610
[   42.318668]  kasan_end_report+0x50/0x50
[   42.322615]  kasan_report+0x144/0x340
[   42.326384]  __asan_report_store8_noabort+0x17/0x20
[   42.331364]  detach_if_pending+0x557/0x610
[   42.335568]  ? trace_raw_output_tick_stop+0x130/0x130
[   42.340727]  ? _raw_spin_lock_irqsave+0x9e/0xc0
[   42.345360]  ? lock_timer_base+0x1a3/0x2b0
[   42.349562]  ? lock_timer_base+0x1eb/0x2b0
[   42.353767]  ? __internal_add_timer+0x2d0/0x2d0
[   42.358404]  ? trace_hardirqs_on+0xd/0x10
[   42.362520]  try_to_del_timer_sync+0xa2/0x120
[   42.366986]  ? del_timer+0x130/0x130
[   42.370667]  ? del_timer_sync+0xeb/0x240
[   42.374714]  del_timer_sync+0x18a/0x240
[   42.378659]  tun_free_netdev+0x105/0x1b0
[   42.382689]  ? tun_xdp+0x410/0x410
[   42.386195]  ? cpumask_next+0x24/0x30
[   42.389965]  ? netdev_refcnt_read+0xed/0x150
[   42.394344]  ? tun_xdp+0x410/0x410
[   42.397851]  netdev_run_todo+0x870/0xca0
[   42.401879]  ? do_group_exit+0x149/0x400
[   42.405909]  ? register_netdev+0x30/0x30
[   42.409942]  ? lock_downgrade+0x990/0x990
[   42.414058]  ? trace_hardirqs_on+0xd/0x10
[   42.418184]  ? refcount_sub_and_test+0x115/0x1b0
[   42.422905]  ? refcount_inc+0x50/0x50
[   42.426674]  ? refcount_inc+0x50/0x50
[   42.430442]  ? sk_destruct+0x4c/0x80
[   42.434120]  ? __sk_free+0x5c/0x230
[   42.437713]  ? sk_free+0x2f/0x40
[   42.441047]  ? __tun_detach+0x176/0x1390
[   42.445081]  ? tun_attach+0xf90/0xf90
[   42.448855]  ? locks_remove_file+0x3fa/0x5a0
[   42.453237]  ? fcntl_setlk+0x10d0/0x10d0
[   42.457270]  ? __fsnotify_parent+0xb4/0x3a0
[   42.461559]  ? fsnotify+0x1af0/0x1af0
[   42.465329]  ? __tun_detach+0x1390/0x1390
[   42.469444]  ? __tun_detach+0x1390/0x1390
[   42.473573]  rtnl_unlock+0xe/0x10
[   42.476994]  tun_chr_close+0x49/0x60
[   42.480690]  __fput+0x333/0x7f0
[   42.483942]  ? fput+0x140/0x140
[   42.487189]  ? check_same_owner+0x320/0x320
[   42.491478]  ____fput+0x15/0x20
[   42.494725]  task_work_run+0x199/0x270
[   42.498581]  ? task_work_cancel+0x210/0x210
[   42.502869]  ? free_nsproxy+0x185/0x1f0
[   42.506811]  ? switch_task_namespaces+0xa2/0xc0
[   42.511450]  do_exit+0x9d2/0x1af0
[   42.514871]  ? trace_hardirqs_on+0xd/0x10
[   42.518987]  ? mm_update_next_owner+0x930/0x930
[   42.523623]  ? mark_held_locks+0xb2/0x100
[   42.527741]  ? kfree+0xe4/0x250
[   42.530988]  ? kvfree+0x36/0x60
[   42.534234]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   42.539216]  ? trace_hardirqs_on+0xd/0x10
[   42.543341]  ? kvfree+0x3b/0x60
[   42.546601]  ? rtnl_unlock+0xe/0x10
[   42.550190]  ? __tun_chr_ioctl+0x27a/0x3d20
[   42.554485]  ? find_held_lock+0x39/0x1d0
[   42.558512]  ? __might_sleep+0x95/0x190
[   42.562459]  ? selinux_file_ioctl+0x444/0x690
[   42.566920]  ? __fget_light+0x29d/0x390
[   42.570869]  ? handle_mm_fault+0x410/0x8d0
[   42.575071]  ? tun_chr_compat_ioctl+0x29/0x30
[   42.579535]  ? tun_chr_compat_ioctl+0x29/0x30
[   42.583995]  do_group_exit+0x149/0x400
[   42.587849]  ? __tun_chr_ioctl+0x3d20/0x3d20
[   42.592221]  ? SyS_exit+0x30/0x30