Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 38/75] net: stmmac: fix dropping of multi-descriptor RX frames | Date | Mon, 6 May 2019 16:32:46 +0200 |
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[ 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 cdfe9a350ac0..f2150efddc88 100644 --- a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c +++ b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c @@ -201,6 +201,11 @@ 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++; -- 2.20.1
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