net.ipv6.conf.syz0.accept_dad = 0
net.ipv6.conf.syz0.router_solicitations = 0
executing program
syzkaller login: [   18.108252] ------------[ cut here ]------------
[   18.109813] WARNING: CPU: 3 PID: 3006 at drivers/net/tun.c:1744 tun_get_user+0x2de3/0x36d0
[   18.110536] Kernel panic - not syncing: panic_on_warn set ...
[   18.110536] 
[   18.111131] CPU: 3 PID: 3006 Comm: syzkaller924913 Not tainted 4.14.0-rc5-next-20171018+ #8
[   18.111812] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
[   18.122629] Call Trace:
[   18.122909]  dump_stack+0x194/0x257
[   18.123289]  ? arch_local_irq_restore+0x53/0x53
[   18.123888]  ? vsnprintf+0x1ed/0x1900
[   18.124208]  panic+0x1e4/0x41c
[   18.124432]  ? refcount_error_report+0x214/0x214
[   18.124807]  ? show_regs_print_info+0x65/0x65
[   18.125138]  ? __warn+0x1a9/0x1e0
[   18.125386]  ? tun_get_user+0x2de3/0x36d0
[   18.125707]  __warn+0x1c4/0x1e0
[   18.125983]  ? tun_get_user+0x2de3/0x36d0
[   18.126316]  report_bug+0x211/0x2d0
[   18.126696]  fixup_bug+0x40/0x90
[   18.127048]  do_trap+0x260/0x390
[   18.127558]  do_error_trap+0x120/0x390
[   18.127818]  ? kfree_skbmem+0xe2/0x1d0
[   18.128102]  ? do_trap+0x390/0x390
[   18.128398]  ? __mutex_unlock_slowpath+0xe9/0xac0
[   18.128734]  ? tun_get_user+0x2de3/0x36d0
[   18.129009]  ? wait_for_completion+0x770/0x770
[   18.129382]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   18.129726]  do_invalid_op+0x1b/0x20
[   18.129973]  invalid_op+0x18/0x20
[   18.130224] RIP: 0010:tun_get_user+0x2de3/0x36d0
[   18.130698] RSP: 0018:ffff880039eff730 EFLAGS: 00010286
[   18.131079] RAX: dffffc0000000000 RBX: ffff88006cdf7358 RCX: dffffc0000000000
[   18.131762] RDX: ffffffff87024140 RSI: 0000000000000000 RDI: 0000000000000282
[   18.132507] RBP: ffff880039effae0 R08: 0000000000000001 R09: 0000000000000000
[   18.133228] R10: ffffffff870692e0 R11: 0000000000000000 R12: ffff88006c9e9040
[   18.133940] R13: ffff88006cdf73c8 R14: 0000000000000000 R15: ffff88006d120d80
[   18.134761]  ? __thp_get_unmapped_area+0x130/0x130
[   18.135292]  ? tun_build_skb.isra.48+0x16e0/0x16e0
[   18.135719]  ? kmem_cache_alloc+0x12e/0x760
[   18.136008]  ? do_mmap+0x69b/0xd40
[   18.136257]  ? vm_mmap_pgoff+0x1de/0x280
[   18.136535]  ? SyS_mmap_pgoff+0x23b/0x5f0
[   18.136877]  ? SyS_mmap+0x16/0x20
[   18.137120]  ? entry_SYSCALL_64_fastpath+0x1f/0xbe
[   18.137457]  ? trace_hardirqs_on+0xd/0x10
[   18.137786]  ? check_noncircular+0x20/0x20
[   18.138093]  ? tun_get+0x1ab/0x2e0
[   18.138435]  ? lock_release+0xa40/0xa40
[   18.138936]  ? __lock_is_held+0xb6/0x140
[   18.139361]  ? tun_get+0x1d4/0x2e0
[   18.139653]  ? tun_chr_close+0x60/0x60
[   18.140019]  ? __check_object_size+0x25d/0x4f0
[   18.140467]  ? rcu_note_context_switch+0x710/0x710
[   18.140979]  tun_chr_write_iter+0xb9/0x160
[   18.141319]  do_iter_readv_writev+0x525/0x7f0
[   18.141746]  ? vfs_dedupe_file_range+0x8f0/0x8f0
[   18.142104]  ? rw_verify_area+0xe5/0x2b0
[   18.142977]  do_iter_write+0x154/0x540
[   18.143288]  ? dup_iter+0x260/0x260
[   18.143654]  ? handle_mm_fault+0x410/0x8d0
[   18.144015]  ? __do_page_fault+0x31e/0xd60
[   18.144311]  vfs_writev+0x18a/0x340
[   18.144628]  ? __fget_light+0x297/0x380
[   18.145004]  ? vfs_iter_write+0xb0/0xb0
[   18.145419]  ? __do_page_fault+0x3d6/0xd60
[   18.145845]  ? down_read_killable+0x180/0x180
[   18.146314]  ? mm_fault_error+0x2c0/0x2c0
[   18.146808]  ? vm_mmap_pgoff+0x13b/0x280
[   18.147249]  ? __fdget_pos+0x130/0x190
[   18.147656]  ? do_page_fault+0xee/0x720
[   18.148067]  ? __fdget_raw+0x20/0x20
[   18.148443]  ? __do_page_fault+0xd60/0xd60
[   18.148897]  do_writev+0xfc/0x2a0
[   18.149241]  ? do_writev+0xfc/0x2a0
[   18.149537]  ? vfs_writev+0x340/0x340
[   18.149790]  ? entry_SYSCALL_64_fastpath+0x5/0xbe
[   18.150164]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   18.150776]  SyS_writev+0x27/0x30
[   18.151149]  entry_SYSCALL_64_fastpath+0x1f/0xbe
[   18.151623] RIP: 0033:0x439ea7
[   18.151945] RSP: 002b:00007ffcdf5e0388 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
[   18.152728] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000439ea7
[   18.153461] RDX: 0000000000000002 RSI: 00007ffcdf5e03a0 RDI: 0000000000000003
[   18.154189] RBP: 0000000000000082 R08: 000000000000007a R09: 0000000000000004
[   18.154994] R10: 000000000007adef R11: 0000000000000246 R12: 0000000000000000
[   18.155717] R13: 00000000004024c0 R14: 0000000000402550 R15: 0000000000000000
[   18.159020] Dumping ftrace buffer:
[   18.159373]    (ftrace buffer empty)
[   18.159700] Kernel Offset: disabled
[   18.159951] Rebooting in 86400 seconds..