net.ipv6.conf.syz0.accept_dad = 0
net.ipv6.conf.syz0.router_solicitations = 0
syzkaller login: [   18.141761] ------------[ cut here ]------------
[   18.142257] WARNING: CPU: 2 PID: 3010 at drivers/net/tun.c:1744 tun_get_user+0x2de3/0x36d0
executing program
[   18.148854] Kernel panic - not syncing: panic_on_warn set ...
[   18.148854] 
[   18.151366] CPU: 3 PID: 3010 Comm: syzkaller411875 Not tainted 4.14.0-rc5-next-20171018+ #8
[   18.152187] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
[   18.152949] Call Trace:
[   18.153197]  dump_stack+0x194/0x257
[   18.153542]  ? arch_local_irq_restore+0x53/0x53
[   18.154088]  ? vsnprintf+0x1ed/0x1900
[   18.154456]  panic+0x1e4/0x41c
[   18.154761]  ? refcount_error_report+0x214/0x214
[   18.155204]  ? show_regs_print_info+0x65/0x65
[   18.155581]  ? __warn+0x1a9/0x1e0
[   18.155856]  ? tun_get_user+0x2de3/0x36d0
[   18.156197]  __warn+0x1c4/0x1e0
[   18.156589]  ? tun_get_user+0x2de3/0x36d0
[   18.157371]  report_bug+0x211/0x2d0
[   18.157781]  fixup_bug+0x40/0x90
[   18.158169]  do_trap+0x260/0x390
[   18.158512]  do_error_trap+0x120/0x390
[   18.158888]  ? kfree_skbmem+0xe2/0x1d0
[   18.159326]  ? do_trap+0x390/0x390
[   18.159723]  ? __mutex_unlock_slowpath+0xe9/0xac0
[   18.160235]  ? tun_get_user+0x2de3/0x36d0
[   18.160912]  ? wait_for_completion+0x770/0x770
[   18.161301]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   18.161714]  do_invalid_op+0x1b/0x20
[   18.162037]  invalid_op+0x18/0x20
[   18.162336] RIP: 0010:tun_get_user+0x2de3/0x36d0
[   18.162746] RSP: 0018:ffff8800695cf730 EFLAGS: 00010286
[   18.163435] RAX: dffffc0000000000 RBX: ffff88003c93b058 RCX: dffffc0000000000
[   18.164160] RDX: ffffffff87024140 RSI: 0000000000000000 RDI: 0000000000000282
[   18.164787] RBP: ffff8800695cfae0 R08: 0000000000000001 R09: 0000000000000000
[   18.165777] R10: ffffffff870692e0 R11: 0000000000000000 R12: ffff8800683ad1c0
[   18.166388] R13: ffff88003c93b0c8 R14: 0000000000000000 R15: ffff880039bf8bc0
[   18.166988]  ? __thp_get_unmapped_area+0x130/0x130
[   18.167409]  ? tun_build_skb.isra.48+0x16e0/0x16e0
[   18.167822]  ? __bpf_prog_release+0xb1/0xf0
[   18.168201]  ? bpf_prepare_filter+0x2e7/0xe00
[   18.168583]  ? check_noncircular+0x20/0x20
[   18.168946]  ? tun_get+0x1ab/0x2e0
[   18.169254]  ? do_seccomp+0x1c7b/0x21f0
[   18.169583]  ? lock_release+0xa40/0xa40
[   18.169912]  ? __lock_is_held+0xb6/0x140
[   18.170260]  ? tun_get+0x1d4/0x2e0
[   18.170575]  ? tun_chr_close+0x60/0x60
[   18.170864]  ? __check_object_size+0x25d/0x4f0
[   18.171329]  ? rcu_note_context_switch+0x710/0x710
[   18.171837]  tun_chr_write_iter+0xb9/0x160
[   18.172214]  do_iter_readv_writev+0x525/0x7f0
[   18.172591]  ? vfs_dedupe_file_range+0x8f0/0x8f0
[   18.172989]  ? rw_verify_area+0xe5/0x2b0
[   18.173361]  do_iter_write+0x154/0x540
[   18.173690]  ? dup_iter+0x260/0x260
[   18.173991]  ? handle_mm_fault+0x410/0x8d0
[   18.174365]  ? __do_page_fault+0x31e/0xd60
[   18.174747]  vfs_writev+0x18a/0x340
[   18.175075]  ? __fget_light+0x297/0x380
[   18.175432]  ? vfs_iter_write+0xb0/0xb0
[   18.175769]  ? __do_page_fault+0x3d6/0xd60
[   18.176115]  ? down_read_killable+0x180/0x180
[   18.176458]  ? mm_fault_error+0x2c0/0x2c0
[   18.176810]  ? vm_mmap_pgoff+0x13b/0x280
[   18.177166]  ? __fdget_pos+0x130/0x190
[   18.177455]  ? do_page_fault+0xee/0x720
[   18.177767]  ? __fdget_raw+0x20/0x20
[   18.178090]  ? __do_page_fault+0xd60/0xd60
[   18.178449]  do_writev+0xfc/0x2a0
[   18.178736]  ? do_writev+0xfc/0x2a0
[   18.179077]  ? vfs_writev+0x340/0x340
[   18.179449]  ? entry_SYSCALL_64_fastpath+0x5/0xbe
[   18.179933]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   18.180463]  SyS_writev+0x27/0x30
[   18.180825]  entry_SYSCALL_64_fastpath+0x1f/0xbe
[   18.181288] RIP: 0033:0x439de7
[   18.181608] RSP: 002b:00007ffeafca0b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
[   18.182392] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000439de7
[   18.183131] RDX: 0000000000000002 RSI: 00007ffeafca0b40 RDI: 0000000000000003
[   18.183873] RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000001
[   18.185082] R10: 0000000002000004 R11: 0000000000000246 R12: 0000000000000000
[   18.185688] R13: 0000000000402400 R14: 0000000000402490 R15: 0000000000000000
[   18.186937] Dumping ftrace buffer:
[   18.187332]    (ftrace buffer empty)
[   18.187639] Kernel Offset: disabled
[   18.187951] Rebooting in 86400 seconds..