Debian GNU/Linux 7 syzkaller ttyS0

net.ipv6.conf.syz0.accept_dad = 0
net.ipv6.conf.syz0.router_solicitations = 0
syzkaller login: [   18.561827] ------------[ cut here ]------------
[   18.562307] WARNING: CPU: 3 PID: 2996 at drivers/net/tun.c:1744 tun_get_user+0x2de3/0x36d0
[   18.563209] Kernel panic - not syncing: panic_on_warn set ...
[   18.563209] 
executing program
[   18.563881] CPU: 3 PID: 2996 Comm: syzkaller633888 Not tainted 4.14.0-rc5-next-20171018+ #8
[   18.565094] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
[   18.565890] Call Trace:
[   18.566154]  dump_stack+0x194/0x257
[   18.566518]  ? arch_local_irq_restore+0x53/0x53
[   18.567279]  ? vsnprintf+0x1ed/0x1900
[   18.567638]  panic+0x1e4/0x41c
[   18.567990]  ? refcount_error_report+0x214/0x214
[   18.571287]  ? show_regs_print_info+0x65/0x65
[   18.571572]  ? __warn+0x1a9/0x1e0
[   18.571790]  ? tun_get_user+0x2de3/0x36d0
[   18.572088]  __warn+0x1c4/0x1e0
[   18.572309]  ? tun_get_user+0x2de3/0x36d0
[   18.572573]  report_bug+0x211/0x2d0
[   18.572802]  fixup_bug+0x40/0x90
[   18.573020]  do_trap+0x260/0x390
[   18.573247]  do_error_trap+0x120/0x390
[   18.573493]  ? kfree_skbmem+0xe2/0x1d0
[   18.573739]  ? do_trap+0x390/0x390
[   18.573959]  ? __mutex_unlock_slowpath+0xe9/0xac0
[   18.574277]  ? tun_get_user+0x2de3/0x36d0
[   18.574533]  ? wait_for_completion+0x770/0x770
[   18.574836]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   18.575146]  do_invalid_op+0x1b/0x20
[   18.575387]  invalid_op+0x18/0x20
[   18.575697] RIP: 0010:tun_get_user+0x2de3/0x36d0
[   18.576429] RSP: 0018:ffff88003dd8f730 EFLAGS: 00010286
[   18.576746] RAX: dffffc0000000000 RBX: ffff88006cfb4dd8 RCX: dffffc0000000000
[   18.577188] RDX: ffffffff87024140 RSI: 0000000000000000 RDI: 0000000000000282
[   18.577621] RBP: ffff88003dd8fae0 R08: 0000000000000001 R09: 0000000000000000
[   18.578053] R10: ffffffff870692e0 R11: 0000000000000000 R12: ffff880069dca400
[   18.578494] R13: ffff88006cfb4e48 R14: 0000000000000000 R15: ffff88006a3f0d40
[   18.578940]  ? __thp_get_unmapped_area+0x130/0x130
[   18.579257]  ? tun_build_skb.isra.48+0x16e0/0x16e0
[   18.579557]  ? kmem_cache_alloc+0x12e/0x760
[   18.579820]  ? do_mmap+0x69b/0xd40
[   18.580233]  ? vm_mmap_pgoff+0x1de/0x280
[   18.580491]  ? SyS_mmap_pgoff+0x23b/0x5f0
[   18.580749]  ? SyS_mmap+0x16/0x20
[   18.580957]  ? entry_SYSCALL_64_fastpath+0x1f/0xbe
[   18.581282]  ? trace_hardirqs_on+0xd/0x10
[   18.581552]  ? check_noncircular+0x20/0x20
[   18.581816]  ? tun_get+0x1ab/0x2e0
[   18.582051]  ? lock_release+0xa40/0xa40
[   18.582297]  ? __lock_is_held+0xb6/0x140
[   18.582559]  ? tun_get+0x1d4/0x2e0
[   18.582771]  ? tun_chr_close+0x60/0x60
[   18.583006]  ? __check_object_size+0x25d/0x4f0
[   18.583299]  ? rcu_note_context_switch+0x710/0x710
[   18.583617]  tun_chr_write_iter+0xb9/0x160
[   18.583872]  do_iter_readv_writev+0x525/0x7f0
[   18.584244]  ? vfs_dedupe_file_range+0x8f0/0x8f0
[   18.584545]  ? rw_verify_area+0xe5/0x2b0
[   18.584790]  do_iter_write+0x154/0x540
[   18.585038]  ? dup_iter+0x260/0x260
[   18.585261]  ? handle_mm_fault+0x410/0x8d0
[   18.585524]  ? __do_page_fault+0x31e/0xd60
[   18.585779]  vfs_writev+0x18a/0x340
[   18.585993]  ? __fget_light+0x297/0x380
[   18.586245]  ? vfs_iter_write+0xb0/0xb0
[   18.586495]  ? __do_page_fault+0x3d6/0xd60
[   18.586746]  ? down_read_killable+0x180/0x180
[   18.587024]  ? mm_fault_error+0x2c0/0x2c0
[   18.587642]  ? vm_mmap_pgoff+0x13b/0x280
[   18.587926]  ? __fdget_pos+0x130/0x190
[   18.588208]  ? do_page_fault+0xee/0x720
[   18.588451]  ? __fdget_raw+0x20/0x20
[   18.588680]  ? __do_page_fault+0xd60/0xd60
[   18.588949]  do_writev+0xfc/0x2a0
[   18.589175]  ? do_writev+0xfc/0x2a0
[   18.589395]  ? vfs_writev+0x340/0x340
[   18.589626]  ? entry_SYSCALL_64_fastpath+0x5/0xbe
[   18.589948]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   18.590290]  SyS_writev+0x27/0x30
[   18.590509]  entry_SYSCALL_64_fastpath+0x1f/0xbe
[   18.590795] RIP: 0033:0x439dc7
[   18.590998] RSP: 002b:00007ffe8a018c48 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
[   18.591471] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000439dc7
[   18.591913] RDX: 0000000000000002 RSI: 00007ffe8a018c60 RDI: 0000000000000003
[   18.596804] RBP: 0000000000000082 R08: 000000000000003e R09: 0000000000000004
[   18.597515] R10: 00000000aaaaaaaa R11: 0000000000000246 R12: 0000000000000000
[   18.598240] R13: 00000000004023e0 R14: 0000000000402470 R15: 0000000000000000
[   18.599603] Dumping ftrace buffer:
[   18.600008]    (ftrace buffer empty)
[   18.601667] Kernel Offset: disabled
[   18.601917] Rebooting in 86400 seconds..