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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 0CC95C4CED0 for ; Thu, 19 Sep 2019 14:29:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E15352053B for ; Thu, 19 Sep 2019 14:29:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390798AbfISO3s (ORCPT ); Thu, 19 Sep 2019 10:29:48 -0400 Received: from mx1.emlix.com ([188.40.240.192]:58592 "EHLO mx1.emlix.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731224AbfISO3r (ORCPT ); Thu, 19 Sep 2019 10:29:47 -0400 Received: from mailer.emlix.com (unknown [81.20.119.6]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.emlix.com (Postfix) with ESMTPS id 03755600E3; Thu, 19 Sep 2019 16:29:46 +0200 (CEST) From: Philipp Puschmann To: linux-kernel@vger.kernel.org Cc: yibin.gong@nxp.com, fugang.duan@nxp.com, l.stach@pengutronix.de, dan.j.williams@intel.com, vkoul@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, linux-imx@nxp.com, dmaengine@vger.kernel.or, linux-arm-kernel@lists.infradead.org, Philipp Puschmann Subject: [PATCH v4 1/3] dmaengine: imx-sdma: fix buffer ownership Date: Thu, 19 Sep 2019 16:29:39 +0200 Message-Id: <20190919142942.12469-2-philipp.puschmann@emlix.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190919142942.12469-1-philipp.puschmann@emlix.com> References: <20190919142942.12469-1-philipp.puschmann@emlix.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org BD_DONE flag marks ownership of the buffer. When 1 SDMA owns the buffer, when 0 ARM owns it. When processing the buffers in sdma_update_channel_loop the ownership of the currently processed buffer was set to SDMA again before running the callback function of the buffer and while the sdma script may be running in parallel. So there was the possibility to get the buffer overwritten by SDMA before it has been processed by kernel leading to kind of random errors in the upper layers, e.g. bluetooth. Fixes: 1ec1e82f2510 ("dmaengine: Add Freescale i.MX SDMA support") Signed-off-by: Philipp Puschmann --- Changelog v4: - fixed the fixes tag Changelog v3: - use correct dma_wmb() instead of dma_wb() - add fixes tag Changelog v2: - add dma_wb() drivers/dma/imx-sdma.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c index 9ba74ab7e912..e029a2443cfc 100644 --- a/drivers/dma/imx-sdma.c +++ b/drivers/dma/imx-sdma.c @@ -802,7 +802,6 @@ static void sdma_update_channel_loop(struct sdma_channel *sdmac) */ desc->chn_real_count = bd->mode.count; - bd->mode.status |= BD_DONE; bd->mode.count = desc->period_len; desc->buf_ptail = desc->buf_tail; desc->buf_tail = (desc->buf_tail + 1) % desc->num_bd; @@ -817,6 +816,9 @@ static void sdma_update_channel_loop(struct sdma_channel *sdmac) dmaengine_desc_get_callback_invoke(&desc->vd.tx, NULL); spin_lock(&sdmac->vc.lock); + dma_wmb(); + bd->mode.status |= BD_DONE; + if (error) sdmac->status = old_status; } -- 2.23.0