If we disabled IPv6 from kernel boot up cmd(ipv6.disable=1), we should not call ip6_err_gen_icmpv6_unreach().
Reproducer: ip link add sit1 type sit local 10.10.0.1 remote 10.10.1.1 ttl 1 ip link set sit1 up ip addr add 192.168.0.1/24 dev sit1 ping 192.168.0.2 Reported-by: Jianlin Shi <ji...@redhat.com> Signed-off-by: Hangbin Liu <liuhang...@gmail.com> --- net/ipv6/sit.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index 1e03305c0549..e43fbac0fd1a 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -493,6 +493,7 @@ static int ipip6_err(struct sk_buff *skb, u32 info) const int type = icmp_hdr(skb)->type; const int code = icmp_hdr(skb)->code; unsigned int data_len = 0; + struct inet6_dev *idev; struct ip_tunnel *t; int sifindex; int err; @@ -546,8 +547,13 @@ static int ipip6_err(struct sk_buff *skb, u32 info) } err = 0; - if (!ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len)) + + idev = in6_dev_get(skb->dev); + if (idev && + !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len)) { + in6_dev_put(idev); goto out; + } if (t->parms.iph.daddr == 0) goto out; -- 2.19.2