net: don't call update_pmtu unconditionally
Some dst_ops (e.g. md_dst_ops)) doesn't set this handler. It may result to:
"BUG: unable to handle kernel NULL pointer dereference at (null)"
Let's add a helper to check if update_pmtu is available before calling it.
Fixes: 52a589d51f10 ("geneve: update skb dst pmtu on tx path")
Fixes: a93bf0ff4490 ("vxlan: update skb dst pmtu on tx path")
CC: Roman Kapl <code@rkapl.cz>
CC: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/dst.h b/include/net/dst.h
index b091fd5..d49d607 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -521,4 +521,12 @@ static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
}
#endif
+static inline void skb_dst_update_pmtu(struct sk_buff *skb, u32 mtu)
+{
+ struct dst_entry *dst = skb_dst(skb);
+
+ if (dst && dst->ops->update_pmtu)
+ dst->ops->update_pmtu(dst, NULL, skb, mtu);
+}
+
#endif /* _NET_DST_H */