From: Felix Fietkau <nbd@nbd.name>
Date: Tue, 15 Oct 2024 10:13:55 +0200
Subject: [PATCH] net: ethernet: mtk_eth_soc: fix memory corruption during fq
 dma init

The loop responsible for allocating up to MTK_FQ_DMA_LENGTH buffers must
only touch as many descriptors, otherwise it ends up corrupting unrelated
memory. Fix the loop iteration count accordingly.

Fixes: c57e55819443 ("net: ethernet: mtk_eth_soc: handle dma buffer size soc specific")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -1172,7 +1172,7 @@ static int mtk_init_fq_dma(struct mtk_et
 		if (unlikely(dma_mapping_error(eth->dma_dev, dma_addr)))
 			return -ENOMEM;
 
-		for (i = 0; i < cnt; i++) {
+		for (i = 0; i < len; i++) {
 			struct mtk_tx_dma_v2 *txd;
 
 			txd = eth->scratch_ring + (j * MTK_FQ_DMA_LENGTH + i) * soc->tx.desc_size;