bgmac: fix a missing check for build_skb

wangweidong · davem330 · commit f1640c3ddeec · 2016-01-13T00:24:14.000-05:00
when build_skb failed, it may occure a NULL pointer.
So add a 'NULL check' for it.

Signed-off-by: Weidong Wang &lt;wangweidong1@huawei.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c
@@ -466,6 +466,11 @@ static int bgmac_dma_rx_read(struct bgmac *bgmac, struct bgmac_dma_ring *ring,
 			len -= ETH_FCS_LEN;
 
 			skb = build_skb(buf, BGMAC_RX_ALLOC_SIZE);
+			if (unlikely(skb)) {
+				bgmac_err(bgmac, "build_skb failed\n");
+				put_page(virt_to_head_page(buf));
+				break;
+			}
 			skb_put(skb, BGMAC_RX_FRAME_OFFSET +
 				BGMAC_RX_BUF_OFFSET + len);
 			skb_pull(skb, BGMAC_RX_FRAME_OFFSET +
