lkml.org 
[lkml]   [2019]   [Apr]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH AUTOSEL 4.9 12/28] net: stmmac: fix dropping of multi-descriptor RX frames
Date
From: Aaro Koskinen <aaro.koskinen@nokia.com>

[ 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++;
--
2.19.1
\
 
 \ /
  Last update: 2019-04-24 16:56    [W:0.094 / U:0.476 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site