When we add a new GENEVE device with IPv6 remote, checking only for IS_ENABLED(CONFIG_IPV6) is not enough as we may disable IPv6 in the kernel command line (ipv6.disable=1), and calling rt6_lookup() would cause a NULL pointer dereference.
v2: - don't mix declarations and code (reported by Stefano Brivio, Eric Dumazet) - there's no need to use in6_dev_get() as we only need to check that idev exists (reported by David Ahern). This is under RTNL, so we can simply use __in6_dev_get() instead (Stefano, Eric). Reported-by: Jianlin Shi <[email protected]> Fixes: c40e89fd358e9 ("geneve: configure MTU based on a lower device") Cc: Alexey Kodanev <[email protected]> Signed-off-by: Hangbin Liu <[email protected]> Reviewed-by: Stefano Brivio <[email protected]> --- drivers/net/geneve.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index 58bbba8582b0..3377ac66a347 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -1512,9 +1512,13 @@ static void geneve_link_config(struct net_device *dev, } #if IS_ENABLED(CONFIG_IPV6) case AF_INET6: { - struct rt6_info *rt = rt6_lookup(geneve->net, - &info->key.u.ipv6.dst, NULL, 0, - NULL, 0); + struct rt6_info *rt; + + if (!__in6_dev_get(dev)) + break; + + rt = rt6_lookup(geneve->net, &info->key.u.ipv6.dst, NULL, 0, + NULL, 0); if (rt && rt->dst.dev) ldev_mtu = rt->dst.dev->mtu - GENEVE_IPV6_HLEN; -- 2.19.2
