On 2/6/19 4:51 AM, Hangbin Liu wrote:
> 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 kernel
> cmd(ipv6.disable=1), which will cause a NULL pointer dereference.
>
> Reported-by: Jianlin Shi <ji...@redhat.com>
> Signed-off-by: Hangbin Liu <liuhang...@gmail.com>
> ---
> drivers/net/geneve.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
> index 58bbba8582b0..0658715581e3 100644
> --- a/drivers/net/geneve.c
> +++ b/drivers/net/geneve.c
> @@ -1512,6 +1512,10 @@ static void geneve_link_config(struct net_device *dev,
> }
> #if IS_ENABLED(CONFIG_IPV6)
> case AF_INET6: {
> + struct inet6_dev *idev = in6_dev_get(dev);
> + if (!idev)
> + break;
Since you don't need an idev reference rcu_access_pointer should be
enough to say v6 is enabled on this device. ie., add a helper to check
that rcu_access_pointer(dev->ip6_ptr) is non-NULL
