From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 08F55C04AA6 for ; Mon, 29 Apr 2019 11:36:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C9066215EA for ; Mon, 29 Apr 2019 11:36:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556537769; bh=xrb4idnEqTxEw7YKrCpZyBX26GxTnwHkDH99g213PQY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=MPl5fCmMH7bFhDOphHBQhEYcc7h4eA+FbyhxyGtXxk2mV0gbSB4WMVlGieI8z/P3S 0X5qQOwP/fEWVLG2A2ysA0KoXgillqGkYAvzptw1F/L8+n3g8HyllMmRQBUmIafXtn HEH+XmD6C77CiR4xfvQdRFZhy2iw8ADWKdJ0XCAg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728034AbfD2LgI (ORCPT ); Mon, 29 Apr 2019 07:36:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:43518 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727986AbfD2LgH (ORCPT ); Mon, 29 Apr 2019 07:36:07 -0400 Received: from localhost (unknown [171.76.113.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B69482075E; Mon, 29 Apr 2019 11:36:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556537766; bh=xrb4idnEqTxEw7YKrCpZyBX26GxTnwHkDH99g213PQY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VEW+K+47fN2uG7Z1EKCt2g8fTb1RQbfUPM6mxN3KWl5FiTdqryFkRGMrfXCZje2El EeJIuGirmR+BnFAi+o/wbYHW29KWlDOoHDWrqRXlEFFUwVN8kKX/1JWTGcAJMeT3Y5 bvzr+DdI92iexlvpfVvTrkptqj5Xg8GNxGNLIudI= Date: Mon, 29 Apr 2019 17:05:55 +0530 From: Vinod Koul To: Baolin Wang Cc: dan.j.williams@intel.com, eric.long@unisoc.com, orsonzhai@gmail.com, zhang.lyra@gmail.com, broonie@kernel.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/7] dmaengine: sprd: Fix the possible crash when getting engine status Message-ID: <20190429113555.GI3845@vkoul-mobl.Dlink> References: <2eecd528e85377f03e6fbc5e7d6544b9c9f59cb1.1555330115.git.baolin.wang@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2eecd528e85377f03e6fbc5e7d6544b9c9f59cb1.1555330115.git.baolin.wang@linaro.org> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15-04-19, 20:14, Baolin Wang wrote: > We will get a NULL virtual descriptor by vchan_find_desc() when the descriptor > has been submitted, that will crash the kernel when getting the engine status. No that is wrong, status is for descriptor and not engine! > In this case, since the descriptor has been submitted, which means the pointer > 'schan->cur_desc' will point to the current descriptor, then we can use > 'schan->cur_desc' to get the engine status to avoid this issue. Nope, since the descriptor is completed, you return with residue as 0 and DMA_COMPLETE status! > > Signed-off-by: Baolin Wang > --- > drivers/dma/sprd-dma.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c > index 48431e2..e29342a 100644 > --- a/drivers/dma/sprd-dma.c > +++ b/drivers/dma/sprd-dma.c > @@ -625,7 +625,7 @@ static enum dma_status sprd_dma_tx_status(struct dma_chan *chan, > else > pos = 0; > } else if (schan->cur_desc && schan->cur_desc->vd.tx.cookie == cookie) { > - struct sprd_dma_desc *sdesc = to_sprd_dma_desc(vd); > + struct sprd_dma_desc *sdesc = schan->cur_desc; > > if (sdesc->dir == DMA_DEV_TO_MEM) > pos = sprd_dma_get_dst_addr(schan); > -- > 1.7.9.5 -- ~Vinod