From: Felix Fietkau <nbd@openwrt.org>
Date: Sun, 12 Apr 2015 22:28:20 +0200
Subject: [PATCH] bgmac: add check for oversized packets

In very rare cases, the MAC can catch an internal buffer that is bigger
than it's supposed to be. Instead of crashing the kernel, simply pass
the buffer back to the hardware

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---

--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -445,6 +445,13 @@ static int bgmac_dma_rx_read(struct bgma
 				break;
 			}
 
+			if (len > BGMAC_RX_ALLOC_SIZE) {
+				bgmac_err(bgmac, "Found oversized packet at slot %d, DMA issue!\n",
+					  ring->start);
+				put_page(virt_to_head_page(buf));
+				break;
+			}
+
 			/* Omit CRC. */
 			len -= ETH_FCS_LEN;