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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 64D59C76191 for ; Fri, 26 Jul 2019 13:48:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2F31E22CD8 for ; Fri, 26 Jul 2019 13:48:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564148883; bh=f8LvDihBYfADIjCThN3i3ijbr8O455t6YObrPM4vvV4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mExAxmfd9G4qr4rd18VQUKKm0R+/XMfQTRJ+1lP2z5hQjaaHTSozvVy5tvPbVeFjN GFV3pFFrBXiriFOXwF5dLuUQtLio2xOPEREQP2+xBeyMueeE6M1sInf2LNYHAdgKD6 RvRynwEZAFNr9krhHRS+XkYUpYGzIi5NHp3nLb8c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728173AbfGZNpg (ORCPT ); Fri, 26 Jul 2019 09:45:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:54652 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728170AbfGZNpg (ORCPT ); Fri, 26 Jul 2019 09:45:36 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5C3D422CBF; Fri, 26 Jul 2019 13:45:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564148735; bh=f8LvDihBYfADIjCThN3i3ijbr8O455t6YObrPM4vvV4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2CXCYJQArZIE9oj6QswS8y+cydcQllgQWegYuFxGCe59hTG0eRtjJ94wVFNcyMjYN CcMvOBjUqWYz+w6APUwGS1VjlVIL/nl32S/zWHGZgbMs9DEfvRIST/YNKCy/Rfogpx ME7G0qtWaPLswe6LRaKTwG9OqEx3nMwFGxB9lWww= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Geert Uytterhoeven , Eugeniu Rosca , Yoshihiro Shimoda , Vinod Koul , Sasha Levin , dmaengine@vger.kernel.org Subject: [PATCH AUTOSEL 4.4 05/23] dmaengine: rcar-dmac: Reject zero-length slave DMA requests Date: Fri, 26 Jul 2019 09:45:04 -0400 Message-Id: <20190726134522.13308-5-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190726134522.13308-1-sashal@kernel.org> References: <20190726134522.13308-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org From: Geert Uytterhoeven [ Upstream commit 78efb76ab4dfb8f74f290ae743f34162cd627f19 ] While the .device_prep_slave_sg() callback rejects empty scatterlists, it still accepts single-entry scatterlists with a zero-length segment. These may happen if a driver calls dmaengine_prep_slave_single() with a zero len parameter. The corresponding DMA request will never complete, leading to messages like: rcar-dmac e7300000.dma-controller: Channel Address Error happen and DMA timeouts. Although requesting a zero-length DMA request is a driver bug, rejecting it early eases debugging. Note that the .device_prep_dma_memcpy() callback already rejects requests to copy zero bytes. Reported-by: Eugeniu Rosca Analyzed-by: Yoshihiro Shimoda Signed-off-by: Geert Uytterhoeven Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin --- drivers/dma/sh/rcar-dmac.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c index 2b36d1c63aa5..956189a1ba81 100644 --- a/drivers/dma/sh/rcar-dmac.c +++ b/drivers/dma/sh/rcar-dmac.c @@ -1030,7 +1030,7 @@ rcar_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, dma_addr_t dev_addr; /* Someone calling slave DMA on a generic channel? */ - if (rchan->mid_rid < 0 || !sg_len) { + if (rchan->mid_rid < 0 || !sg_len || !sg_dma_len(sgl)) { dev_warn(chan->device->dev, "%s: bad parameter: len=%d, id=%d\n", __func__, sg_len, rchan->mid_rid); -- 2.20.1