diff mbox series

[5.4,30/90] lantiq: net: fix duplicated skb in rx descriptor ring

Message ID 20210621154905.134987695@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH June 21, 2021, 4:15 p.m. UTC 
From: Aleksander Jan Bajkowski <olek2@wp.pl>

[ Upstream commit 7ea6cd16f1599c1eac6018751eadbc5fc736b99a ]

The previous commit didn't fix the bug properly. By mistake, it replaces
the pointer of the next skb in the descriptor ring instead of the current
one. As a result, the two descriptors are assigned the same SKB. The error
is seen during the iperf test when skb_put tries to insert a second packet
and exceeds the available buffer.

Fixes: c7718ee96dbc ("net: lantiq: fix memory corruption in RX ring ")
Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/lantiq_xrx200.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/lantiq_xrx200.c b/drivers/net/ethernet/lantiq_xrx200.c
index 8d073b895fc0..6e504854571c 100644
--- a/drivers/net/ethernet/lantiq_xrx200.c
+++ b/drivers/net/ethernet/lantiq_xrx200.c
@@ -154,6 +154,7 @@  static int xrx200_close(struct net_device *net_dev)
 
 static int xrx200_alloc_skb(struct xrx200_chan *ch)
 {
+	struct sk_buff *skb = ch->skb[ch->dma.desc];
 	dma_addr_t mapping;
 	int ret = 0;
 
@@ -168,6 +169,7 @@  static int xrx200_alloc_skb(struct xrx200_chan *ch)
 				 XRX200_DMA_DATA_LEN, DMA_FROM_DEVICE);
 	if (unlikely(dma_mapping_error(ch->priv->dev, mapping))) {
 		dev_kfree_skb_any(ch->skb[ch->dma.desc]);
+		ch->skb[ch->dma.desc] = skb;
 		ret = -ENOMEM;
 		goto skip;
 	}
@@ -198,7 +200,6 @@  static int xrx200_hw_receive(struct xrx200_chan *ch)
 	ch->dma.desc %= LTQ_DESC_NUM;
 
 	if (ret) {
-		ch->skb[ch->dma.desc] = skb;
 		net_dev->stats.rx_dropped++;
 		netdev_err(net_dev, "failed to allocate new rx buffer\n");
 		return ret;