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=-10.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,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 30ED9C43387 for ; Mon, 7 Jan 2019 13:14:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F362F2089F for ; Mon, 7 Jan 2019 13:14:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546866872; bh=Dz5QVBbWarDaea5ke51uUSxhs5Hz05tkbFUhSsFp5MQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=oFrcadeHLaAge4O31kGNmenF0TKNjfnZ9BSRB+nmqoNyBvzSxj1bI1l8qEYcA/Q7+ BdI9P7lIG62Njcng92pNwQo1N+5J+YAnaTCNjXpl81AO6fISAPNTK+gsCbi8QswQdP VvSsTRwGEXSodBDQFNzUQrAbNUPmlrP6KdkrUQBM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732093AbfAGNOa (ORCPT ); Mon, 7 Jan 2019 08:14:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:50430 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730881AbfAGNCz (ORCPT ); Mon, 7 Jan 2019 08:02:55 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 73B7221736; Mon, 7 Jan 2019 13:02:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546866175; bh=Dz5QVBbWarDaea5ke51uUSxhs5Hz05tkbFUhSsFp5MQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YPjvHnKcBA7ohHizXGZtgseNI1MqD+zA6YRz9My23C0jhpRWhffo8MhY53OpxEQTp 46LCERwEIyFS+gXLuElYxAn0YwMV8LtUjbK4xlv+kpDhJkraNzJ/HG1QoJCxtknA71 qZWeVgqHL79gqoIINWXicL+zD0Pjtf8VL+8z2kKs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lukas Wunner , Mathias Duckeck , Frank Pavlic , Martin Sperl , =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= , Mark Brown Subject: [PATCH 4.14 069/101] spi: bcm2835: Fix race on DMA termination Date: Mon, 7 Jan 2019 13:32:57 +0100 Message-Id: <20190107105336.765968953@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190107105330.372621917@linuxfoundation.org> References: <20190107105330.372621917@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore 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 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lukas Wunner commit e82b0b3828451c1cd331d9f304c6078fcd43b62e upstream. If a DMA transfer finishes orderly right when spi_transfer_one_message() determines that it has timed out, the callbacks bcm2835_spi_dma_done() and bcm2835_spi_handle_err() race to call dmaengine_terminate_all(), potentially leading to double termination. Prevent by atomically changing the dma_pending flag before calling dmaengine_terminate_all(). Signed-off-by: Lukas Wunner Fixes: 3ecd37edaa2a ("spi: bcm2835: enable dma modes for transfers meeting certain conditions") Cc: stable@vger.kernel.org # v4.2+ Cc: Mathias Duckeck Cc: Frank Pavlic Cc: Martin Sperl Cc: Noralf Trønnes Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman --- drivers/spi/spi-bcm2835.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -233,10 +233,9 @@ static void bcm2835_spi_dma_done(void *d * is called the tx-dma must have finished - can't get to this * situation otherwise... */ - dmaengine_terminate_all(master->dma_tx); - - /* mark as no longer pending */ - bs->dma_pending = 0; + if (cmpxchg(&bs->dma_pending, true, false)) { + dmaengine_terminate_all(master->dma_tx); + } /* and mark as completed */; complete(&master->xfer_completion); @@ -617,10 +616,9 @@ static void bcm2835_spi_handle_err(struc struct bcm2835_spi *bs = spi_master_get_devdata(master); /* if an error occurred and we have an active dma, then terminate */ - if (bs->dma_pending) { + if (cmpxchg(&bs->dma_pending, true, false)) { dmaengine_terminate_all(master->dma_tx); dmaengine_terminate_all(master->dma_rx); - bs->dma_pending = 0; } /* and reset */ bcm2835_spi_reset_hw(master);