openwrt/target/linux/generic/backport-5.15/750-v6.5-20-net-ethernet-mtk_eth_soc-fix-uninitialized-variable.patch
Daniel Golle 3b86c1f929 kernel: backport two fixes for MediaTek Ethernet driver
Fix PSE port assignment for 3rd GMAC on MT7988 and make sure dma_addr
is always initialized to prevent potentially accessing uninitialized
stack memory in the error path.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
2023-09-11 14:09:48 +01:00

45 lines
1.5 KiB
Diff

From e10a35abb3da12b812cfb6fc6137926a0c81e39a Mon Sep 17 00:00:00 2001
From: Daniel Golle <daniel@makrotopia.org>
Date: Sun, 10 Sep 2023 22:40:30 +0100
Subject: [PATCH] net: ethernet: mtk_eth_soc: fix uninitialized variable
Variable dma_addr in function mtk_poll_rx can be uninitialized on
some of the error paths. In practise this doesn't matter, even random
data present in uninitialized stack memory can safely be used in the
way it happens in the error path.
However, in order to make Smatch happy make sure the variable is
always initialized.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/ethernet/mediatek/mtk_eth_soc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -1941,11 +1941,11 @@ static int mtk_poll_rx(struct napi_struc
u8 *data, *new_data;
struct mtk_rx_dma_v2 *rxd, trxd;
int done = 0, bytes = 0;
+ dma_addr_t dma_addr = DMA_MAPPING_ERROR;
while (done < budget) {
unsigned int pktlen, *rxdcsum;
struct net_device *netdev;
- dma_addr_t dma_addr;
u32 hash, reason;
int mac = 0;
@@ -2122,7 +2122,8 @@ release_desc:
else
rxd->rxd2 = RX_DMA_PREP_PLEN0(ring->buf_size);
- if (MTK_HAS_CAPS(eth->soc->caps, MTK_36BIT_DMA))
+ if (MTK_HAS_CAPS(eth->soc->caps, MTK_36BIT_DMA) &&
+ likely(dma_addr != DMA_MAPPING_ERROR))
rxd->rxd2 |= RX_DMA_PREP_ADDR64(dma_addr);
ring->calc_idx = idx;