[ Upstream commit 8ac0c24fe1c256af6644caf3d311029440ec2fbd ]
Packets without the last descriptor set should be dropped early. If we receive a frame larger than the DMA buffer, the HW will continue using the next descriptor. Driver mistakes these as individual frames, and sometimes a truncated frame (without the LD set) may look like a valid packet.
This fixes a strange issue where the system replies to 4098-byte ping although the MTU/DMA buffer size is set to 4096, and yet at the same time it's logging an oversized packet.
Signed-off-by: Aaro Koskinen aaro.koskinen@nokia.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/stmicro/stmmac/enh_desc.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c index 2c40cafa2619..77dc5842bd0b 100644 --- a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c +++ b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c @@ -205,6 +205,11 @@ static int enh_desc_get_rx_status(void *data, struct stmmac_extra_stats *x, if (unlikely(rdes0 & RDES0_OWN)) return dma_own;
+ if (unlikely(!(rdes0 & RDES0_LAST_DESCRIPTOR))) { + stats->rx_length_errors++; + return discard_frame; + } + if (unlikely(rdes0 & RDES0_ERROR_SUMMARY)) { if (unlikely(rdes0 & RDES0_DESCRIPTOR_ERROR)) { x->rx_desc++;