net.ipv6.conf.syz0.accept_dad = 0
net.ipv6.conf.syz0.router_solicitations = 0
executing program
syzkaller login: [   17.543520] ------------[ cut here ]------------
[   17.544266] WARNING: CPU: 3 PID: 2991 at drivers/net/tun.c:1744 tun_get_user+0x2de3/0x36d0
[   17.545283] Kernel panic - not syncing: panic_on_warn set ...
[   17.545283] 
[   17.545878] CPU: 3 PID: 2991 Comm: syzkaller781592 Not tainted 4.14.0-rc5-next-20171018+ #8
[   17.546487] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
[   17.547117] Call Trace:
[   17.547417]  dump_stack+0x194/0x257
[   17.547753]  ? arch_local_irq_restore+0x53/0x53
[   17.548243]  ? vsnprintf+0x1ed/0x1900
[   17.548634]  panic+0x1e4/0x41c
[   17.548968]  ? refcount_error_report+0x214/0x214
[   17.549444]  ? show_regs_print_info+0x65/0x65
[   17.549907]  ? __warn+0x1a9/0x1e0
[   17.550241]  ? tun_get_user+0x2de3/0x36d0
[   17.550624]  __warn+0x1c4/0x1e0
[   17.550921]  ? tun_get_user+0x2de3/0x36d0
[   17.551300]  report_bug+0x211/0x2d0
[   17.551707]  fixup_bug+0x40/0x90
[   17.552118]  do_trap+0x260/0x390
[   17.552459]  do_error_trap+0x120/0x390
[   17.552862]  ? kfree_skbmem+0xe2/0x1d0
[   17.553256]  ? do_trap+0x390/0x390
[   17.553599]  ? __mutex_unlock_slowpath+0xe9/0xac0
[   17.554077]  ? tun_get_user+0x2de3/0x36d0
[   17.554365]  ? wait_for_completion+0x770/0x770
[   17.554983]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   17.555298]  do_invalid_op+0x1b/0x20
[   17.555521]  invalid_op+0x18/0x20
[   17.555728] RIP: 0010:tun_get_user+0x2de3/0x36d0
[   17.556042] RSP: 0018:ffff880068ecf730 EFLAGS: 00010286
[   17.556359] RAX: dffffc0000000000 RBX: ffff880039cf7a18 RCX: dffffc0000000000
[   17.556786] RDX: ffffffff87024140 RSI: 0000000000000000 RDI: 0000000000000282
[   17.557220] RBP: ffff880068ecfae0 R08: 0000000000000001 R09: 0000000000000000
[   17.557639] R10: ffffffff870692e0 R11: 0000000000000000 R12: ffff8800680cb680
[   17.558087] R13: ffff880039cf7a88 R14: 0000000000000000 R15: ffff88003a0c0d80
[   17.558523]  ? __thp_get_unmapped_area+0x130/0x130
[   17.558822]  ? tun_build_skb.isra.48+0x16e0/0x16e0
[   17.559161]  ? kmem_cache_alloc+0x12e/0x760
[   17.559551]  ? do_mmap+0x69b/0xd40
[   17.559866]  ? vm_mmap_pgoff+0x1de/0x280
[   17.560233]  ? SyS_mmap_pgoff+0x23b/0x5f0
[   17.560600]  ? SyS_mmap+0x16/0x20
[   17.560910]  ? entry_SYSCALL_64_fastpath+0x1f/0xbe
[   17.561236]  ? trace_hardirqs_on+0xd/0x10
[   17.561482]  ? check_noncircular+0x20/0x20
[   17.561752]  ? tun_get+0x1ab/0x2e0
[   17.561997]  ? lock_release+0xa40/0xa40
[   17.562379]  ? __lock_is_held+0xb6/0x140
[   17.562754]  ? tun_get+0x1d4/0x2e0
[   17.563053]  ? tun_chr_close+0x60/0x60
[   17.563322]  ? __check_object_size+0x25d/0x4f0
[   17.563592]  ? rcu_note_context_switch+0x710/0x710
[   17.563885]  tun_chr_write_iter+0xb9/0x160
[   17.564219]  do_iter_readv_writev+0x525/0x7f0
[   17.564506]  ? vfs_dedupe_file_range+0x8f0/0x8f0
[   17.564881]  ? rw_verify_area+0xe5/0x2b0
[   17.565219]  do_iter_write+0x154/0x540
[   17.565533]  ? dup_iter+0x260/0x260
[   17.565872]  ? handle_mm_fault+0x410/0x8d0
[   17.566141]  ? __do_page_fault+0x31e/0xd60
[   17.566396]  vfs_writev+0x18a/0x340
[   17.566609]  ? __fget_light+0x297/0x380
[   17.566926]  ? vfs_iter_write+0xb0/0xb0
[   17.567211]  ? __do_page_fault+0x3d6/0xd60
[   17.567495]  ? down_read_killable+0x180/0x180
[   17.567809]  ? mm_fault_error+0x2c0/0x2c0
[   17.568168]  ? vm_mmap_pgoff+0x13b/0x280
[   17.568432]  ? __fdget_pos+0x130/0x190
[   17.568660]  ? do_page_fault+0xee/0x720
[   17.568990]  ? __fdget_raw+0x20/0x20
[   17.569320]  ? __do_page_fault+0xd60/0xd60
[   17.569697]  do_writev+0xfc/0x2a0
[   17.570001]  ? do_writev+0xfc/0x2a0
[   17.570330]  ? vfs_writev+0x340/0x340
[   17.570667]  ? entry_SYSCALL_64_fastpath+0x5/0xbe
[   17.571098]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   17.571558]  SyS_writev+0x27/0x30
[   17.571837]  entry_SYSCALL_64_fastpath+0x1f/0xbe
[   17.572198] RIP: 0033:0x439c57
[   17.572387] RSP: 002b:00007ffe04da38d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
[   17.572835] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000439c57
[   17.573267] RDX: 0000000000000002 RSI: 00007ffe04da38f0 RDI: 0000000000000003
[   17.573721] RBP: 0000000000000082 R08: 0000000000000011 R09: 0000000000000004
[   17.574210] R10: 0000000068f78f4d R11: 0000000000000246 R12: 0000000000000000
[   17.574632] R13: 0000000000402270 R14: 0000000000402300 R15: 0000000000000000
[   17.575245] Dumping ftrace buffer:
[   17.575522]    (ftrace buffer empty)
[   17.576274] Kernel Offset: disabled
[   17.576496] Rebooting in 86400 seconds..