net: handle the return value of pskb_carve_frag_list() correctly

pskb_carve_frag_list() may return -ENOMEM in pskb_carve_inside_nonlinear().
we should handle this correctly or we would get wrong sk_buff.

Fixes: 6fa01ccd ("skbuff: Add pskb_extract() helper function")
Signed-off-by: NMiaohe Lin <linmiaohe@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/skbuff.c

@@ -5987,9 +5987,13 @@ static int pskb_carve_inside_nonlinear(struct sk_buff *skb, const u32 off,
 	if (skb_has_frag_list(skb))
 		skb_clone_fraglist(skb);
 
-	if (k == 0) {
-		/* split line is in frag list */
-		pskb_carve_frag_list(skb, shinfo, off - pos, gfp_mask);
+	/* split line is in frag list */
+	if (k == 0 && pskb_carve_frag_list(skb, shinfo, off - pos, gfp_mask)) {
+		/* skb_frag_unref() is not needed here as shinfo->nr_frags = 0. */
+		if (skb_has_frag_list(skb))
+			kfree_skb_list(skb_shinfo(skb)->frag_list);
+		kfree(data);
+		return -ENOMEM;
 	}
 	skb_release_data(skb);