[PATCH v3 5/9] bgmac: add check for oversized packets

[Felix Fietkau <nbd@openwrt.org>]

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>
---
 drivers/net/ethernet/broadcom/bgmac.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c
index e004588..3ac8d9a 100644
--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -422,6 +422,14 @@ static int bgmac_dma_rx_read(struct bgmac *bgmac, struct bgmac_dma_ring *ring,
 				break;
 			}
 
+			if (len > BGMAC_RX_ALLOC_SIZE) {
+				bgmac_err(bgmac, "Found oversized packet at slot %d, DMA issue!\n",
+					  ring->start);
+				rx->len = cpu_to_le16(0xdead);
+				rx->flags = cpu_to_le16(0xbeef);
+				break;
+			}
+
 			/* Omit CRC. */
 			len -= ETH_FCS_LEN;
 
-- 
2.2.2