net: amd-xgbe: Fix skb data length underflow

stable inclusion
from stable-v5.10.97
commit 4d3fcfe8464838b3920bc2b939d888e0b792934e
bugzilla: https://gitee.com/openeuler/kernel/issues/I55O0O

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4d3fcfe8464838b3920bc2b939d888e0b792934e

--------------------------------

commit 5aac9108 upstream.

There will be BUG_ON() triggered in include/linux/skbuff.h leading to
intermittent kernel panic, when the skb length underflow is detected.

Fix this by dropping the packet if such length underflows are seen
because of inconsistencies in the hardware descriptors.

Fixes: 622c36f1 ("amd-xgbe: Fix jumbo MTU processing on newer hardware")
Suggested-by: NTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: NShyam Sundar S K <Shyam-sundar.S-k@amd.com>
Acked-by: NTom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20220127092003.2812745-1-Shyam-sundar.S-k@amd.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYu Liao <liaoyu15@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/net/ethernet/amd/xgbe/xgbe-drv.c

@@ -2559,6 +2559,14 @@ static int xgbe_rx_poll(struct xgbe_channel *channel, int budget)
 			buf2_len = xgbe_rx_buf2_len(rdata, packet, len);
 			len += buf2_len;
 
+			if (buf2_len > rdata->rx.buf.dma_len) {
+				/* Hardware inconsistency within the descriptors
+				 * that has resulted in a length underflow.
+				 */
+				error = 1;
+				goto skip_data;
+			}
+
 			if (!skb) {
 				skb = xgbe_create_skb(pdata, napi, rdata,
 						      buf1_len);
@@ -2588,8 +2596,10 @@ static int xgbe_rx_poll(struct xgbe_channel *channel, int budget)
 		if (!last || context_next)
 			goto read_again;
 
-		if (!skb)
+		if (!skb || error) {
+			dev_kfree_skb(skb);
 			goto next_packet;
+		}
 
 		/* Be sure we don't exceed the configured MTU */
 		max_len = netdev->mtu + ETH_HLEN;