From 354e379684fcc70ab8d5450b4d57bd92b5294dfd Mon Sep 17 00:00:00 2001 From: Sergio Paracuellos Date: Sat, 20 Oct 2018 13:31:06 +0200 Subject: [PATCH] staging: mt7621-dma: fix potentially dereferencing uninitialized 'tx_desc' Function 'mtk_hsdma_start_transfer' uses 'tx_desc' pointer which can be dereferenced before it is initializated. Initializate pointer before avoiding the problem. Fixes: 0853c7a53eb3 ("staging: mt7621-dma: ralink: add rt2880 dma engine") Reported-by: Dan Carpenter Signed-off-by: Sergio Paracuellos Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/staging/mt7621-dma/mtk-hsdma.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/staging/mt7621-dma/mtk-hsdma.c b/drivers/staging/mt7621-dma/mtk-hsdma.c index df6ebf41bdea..5831f816c17b 100644 --- a/drivers/staging/mt7621-dma/mtk-hsdma.c +++ b/drivers/staging/mt7621-dma/mtk-hsdma.c @@ -335,6 +335,8 @@ static int mtk_hsdma_start_transfer(struct mtk_hsdam_engine *hsdma, /* tx desc */ src = sg->src_addr; for (i = 0; i < chan->desc->num_sgs; i++) { + tx_desc = &chan->tx_ring[chan->tx_idx]; + if (len > HSDMA_MAX_PLEN) tlen = HSDMA_MAX_PLEN; else @@ -344,7 +346,6 @@ static int mtk_hsdma_start_transfer(struct mtk_hsdam_engine *hsdma, tx_desc->addr1 = src; tx_desc->flags |= HSDMA_DESC_PLEN1(tlen); } else { - tx_desc = &chan->tx_ring[chan->tx_idx]; tx_desc->addr0 = src; tx_desc->flags = HSDMA_DESC_PLEN0(tlen);