From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:37088 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753565AbeBWSey (ORCPT ); Fri, 23 Feb 2018 13:34:54 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Gustavo A. R. Silva" , Ludovic Desroches , Vinod Koul , Sasha Levin Subject: [PATCH 4.4 051/193] dmaengine: at_hdmac: fix potential NULL pointer dereference in atc_prep_dma_interleaved Date: Fri, 23 Feb 2018 19:24:44 +0100 Message-Id: <20180223170334.016821770@linuxfoundation.org> In-Reply-To: <20180223170325.997716448@linuxfoundation.org> References: <20180223170325.997716448@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Gustavo A. R. Silva" [ Upstream commit 62a277d43d47e74972de44d33bd3763e31992414 ] _xt_ is being dereferenced before it is null checked, hence there is a potential null pointer dereference. Fix this by moving the pointer dereference after _xt_ has been null checked. This issue was detected with the help of Coccinelle. Fixes: 4483320e241c ("dmaengine: Use Pointer xt after NULL check.") Signed-off-by: Gustavo A. R. Silva Acked-by: Ludovic Desroches Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/dma/at_hdmac.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -716,7 +716,7 @@ atc_prep_dma_interleaved(struct dma_chan unsigned long flags) { struct at_dma_chan *atchan = to_at_dma_chan(chan); - struct data_chunk *first = xt->sgl; + struct data_chunk *first; struct at_desc *desc = NULL; size_t xfer_count; unsigned int dwidth; @@ -728,6 +728,8 @@ atc_prep_dma_interleaved(struct dma_chan if (unlikely(!xt || xt->numf != 1 || !xt->frame_size)) return NULL; + first = xt->sgl; + dev_info(chan2dev(chan), "%s: src=%pad, dest=%pad, numf=%d, frame_size=%d, flags=0x%lx\n", __func__, &xt->src_start, &xt->dst_start, xt->numf,