skbuff: skb_copy_ubufs must release uarg even without user frags

wdebruij · davem330 · commit b90ddd568792 · 2017-12-21T15:00:58.000-05:00
skb_copy_ubufs creates a private copy of frags[] to release its hold on user frags, then calls uarg->callback to notify the owner. Call uarg->callback even when no frags exist. This edge case can happen when zerocopy_sg_from_iter finds enough room in skb_headlen to copy all the data. Fixes: 3ece782 ("sock: skb_copy_ubufs support for compound pages") Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
@@ -1178,7 +1178,7 @@ int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
 	u32 d_off;
 
 	if (!num_frags)
-		return 0;
+		goto release;
 
 	if (skb_shared(skb) || skb_unclone(skb, gfp_mask))
 		return -EINVAL;
@@ -1238,6 +1238,7 @@ int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
 	__skb_fill_page_desc(skb, new_frags - 1, head, 0, d_off);
 	skb_shinfo(skb)->nr_frags = new_frags;
 
+release:
 	skb_zcopy_clear(skb, false);
 	return 0;
 }
