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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 9FFC2C0650F for ; Mon, 5 Aug 2019 13:09:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6CEE221874 for ; Mon, 5 Aug 2019 13:09:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565010551; bh=vCjxf26LljFZ7AN0o80Vc5x4tVJJM9kGc7NBmOrgOCE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=n7c+ERF0vQjp6zW7CO9ssB7a3FPMx8p0HUL3gmFfZ3m6O5pCxnIz6qwSDlGrJvT5r N6VMgry+qkeRkRl9r7/dyxsxnohA4ExSNL86znSRvzCGg7KqRgqAjVd2PqxfO2QfiG gl8095UG7waygYuHpiWQzKqLkFiLsx8cZTeMe18Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730139AbfHENJK (ORCPT ); Mon, 5 Aug 2019 09:09:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:47382 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729698AbfHENJD (ORCPT ); Mon, 5 Aug 2019 09:09:03 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 D78AF2075B; Mon, 5 Aug 2019 13:09:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565010543; bh=vCjxf26LljFZ7AN0o80Vc5x4tVJJM9kGc7NBmOrgOCE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jOu0LgDiFGYUCTKc+vW0/JOYyJhydj/oNVolukj0n6WhQN/+3xFwYenh+DqRJCZlu Ms3ilNX6baFaPQlmPqo8BWJkzTCGuH/mXcz/81snbapjDlhVTm81ZJqTVH9PKI2eLv vXyc+DsbMZgMrt68PXki/fJs/wboZoB/KpbCpAdQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eugeniu Rosca , Geert Uytterhoeven , Vinod Koul , Sasha Levin , Yoshihiro Shimoda Subject: [PATCH 4.19 11/74] dmaengine: rcar-dmac: Reject zero-length slave DMA requests Date: Mon, 5 Aug 2019 15:02:24 +0200 Message-Id: <20190805124936.716885433@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190805124935.819068648@linuxfoundation.org> References: <20190805124935.819068648@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ 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 0b05a1e08d213..041ce864097e4 100644 --- a/drivers/dma/sh/rcar-dmac.c +++ b/drivers/dma/sh/rcar-dmac.c @@ -1164,7 +1164,7 @@ rcar_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan); /* 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