WARNING in inet6_rt_notify

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=137ff4ecf00000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=29ea624160294967d6c3
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+29ea62...@syzkaller.appspotmail.com

IPv6: ADDRCONF(NETDEV_UP): vlan173: link is not ready
netlink: 16 bytes leftover after parsing attributes in process `syz-executor.1'.
IPv6: RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE
IPv6: NLM_F_CREATE should be set when creating new route
------------[ cut here ]------------
WARNING: CPU: 1 PID: 11588 at net/ipv6/route.c:5064 inet6_rt_notify.cold+0x11/0x18 net/ipv6/route.c:5064
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 11588 Comm: syz-executor.1 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
panic+0x26a/0x50e kernel/panic.c:186
__warn.cold+0x20/0x5a kernel/panic.c:541
report_bug+0x262/0x2b0 lib/bug.c:183
fixup_bug arch/x86/kernel/traps.c:178 [inline]
fixup_bug arch/x86/kernel/traps.c:173 [inline]
do_error_trap+0x1d7/0x310 arch/x86/kernel/traps.c:296
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038
RIP: 0010:inet6_rt_notify.cold+0x11/0x18 net/ipv6/route.c:5064
Code: fe e8 95 5d 4f f9 48 c7 c7 60 59 59 89 e8 f4 8e e0 ff 0f 0b e9 a2 be f5 fe e8 7d 5d 4f f9 48 c7 c7 60 59 59 89 e8 dc 8e e0 ff <0f> 0b e9 08 1d f6 fe e8 65 5d 4f f9 49 bc 00 00 00 00 00 fc ff df
RSP: 0018:ffff88804a887488 EFLAGS: 00010282
RAX: 0000000000000024 RBX: ffff88804a887718 RCX: 0000000000000000
RDX: 000000000003dbe3 RSI: ffffffff814dff01 RDI: ffffed1009510e83
RBP: ffff888051ce1b80 R08: 0000000000000024 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: 00000000ffffffa6
R13: ffff888091094180 R14: ffff88804a887728 R15: 0000000000000000
fib6_add_rt2node net/ipv6/ip6_fib.c:1111 [inline]
fib6_add+0x2800/0x3330 net/ipv6/ip6_fib.c:1328
__ip6_ins_rt net/ipv6/route.c:1170 [inline]
ip6_route_add+0x8b/0x110 net/ipv6/route.c:3227
inet6_rtm_newroute+0x12a/0x140 net/ipv6/route.c:4624
rtnetlink_rcv_msg+0x453/0xb80 net/core/rtnetlink.c:4782
netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463
netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline]
netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351
netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xc3/0x120 net/socket.c:661
___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227
__sys_sendmsg net/socket.c:2265 [inline]
__do_sys_sendmsg net/socket.c:2274 [inline]
__se_sys_sendmsg net/socket.c:2272 [inline]
__x64_sys_sendmsg+0x132/0x220 net/socket.c:2272
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fbd7b4e70e9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbd79e5c168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fbd7b5f9f60 RCX: 00007fbd7b4e70e9
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000004
RBP: 00007fbd7b54108d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe0d02be1f R14: 00007fbd79e5c300 R15: 0000000000022000
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.