ipv6: fix panic when forwarding a pkt with no in6 dev

stable inclusion
from stable-v5.10.112
commit a263712ba8c9ded25dd9d2d5ced11bcea5b33a3e
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5HL0X

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a263712ba8c9ded25dd9d2d5ced11bcea5b33a3e



--------------------------------

commit e3fa461d upstream.

kongweibin reported a kernel panic in ip6_forward() when input interface
has no in6 dev associated.

The following tc commands were used to reproduce this panic:
tc qdisc del dev vxlan100 root
tc qdisc add dev vxlan100 root netem corrupt 5%

CC: stable@vger.kernel.org
Fixes: ccd27f05 ("ipv6: fix 'disable_policy' for fwd packets")
Reported-by: kongweibin <kongweibin2@huawei.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>