Test for cb809def1baaac68ab92

[Shigeru Yoshida]

#syz test

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 2111af022d94..c6439e30e892 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1138,7 +1138,8 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
fib6_set_expires(iter, rt->expires);
fib6_add_gc_list(iter);
}
- if (!(rt->fib6_flags & (RTF_ADDRCONF | RTF_PREFIX_RT))) {
+ if (!(rt->fib6_flags & (RTF_ADDRCONF | RTF_PREFIX_RT)) &&
+ !iter->fib6_nh->fib_nh_gw_family) {
iter->fib6_flags &= ~RTF_ADDRCONF;
iter->fib6_flags &= ~RTF_PREFIX_RT;
}

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+cb809d...@syzkaller.appspotmail.com
Tested-by: syzbot+cb809d...@syzkaller.appspotmail.com

Tested on:

commit: 63804fed Linux 6.19-rc7
git tree: bpf
console output: https://syzkaller.appspot.com/x/log.txt?x=17bd2402580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6e0c3f85f65258ed
dashboard link: https://syzkaller.appspot.com/bug?extid=cb809def1baaac68ab92
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=1232f252580000

Note: testing is done by a robot and is best-effort only.