net: avoid NULL deref in napi_get_frags()

napi_alloc_skb() can return NULL.
We should not crash should this happen.

Fixes: 93f93a440415 ("net: move skb_mark_napi_id() into core networking stack")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/dev.c b/net/core/dev.c
index 41cef3e..5df6cbc 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4390,8 +4390,10 @@ struct sk_buff *napi_get_frags(struct napi_struct *napi)
 
        if (!skb) {
                skb = napi_alloc_skb(napi, GRO_MAX_HEAD);
-               napi->skb = skb;
-               skb_mark_napi_id(skb, napi);
+               if (skb) {
+                       napi->skb = skb;
+                       skb_mark_napi_id(skb, napi);
+               }
        }
        return skb;
 }