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=-10.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 6B77BC43612 for ; Fri, 11 Jan 2019 14:22:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3B0FC2177B for ; Fri, 11 Jan 2019 14:22:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547216546; bh=4stqkj2j/0Rl9oP6ZCWB6uVhGHEVfsFocRqvqhbK9PA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kz9ceP3a8JLGqS0egGZTqoBPKMwjwDmRl17RBM3ryzpTUO8iufObkeBhVtEuk1x/g F9nYZpqRu/3tVFQbV5PKLsYLGRiR/3PfeY8x5bJc++tY/n96sh4lT0VYc1friWvLNT faguzdQ44+5EbaOENcGX1u2fGlg/c//ARdDcwXRc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731836AbfAKOT0 (ORCPT ); Fri, 11 Jan 2019 09:19:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:36386 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729359AbfAKOTZ (ORCPT ); Fri, 11 Jan 2019 09:19:25 -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 96E1421783; Fri, 11 Jan 2019 14:19:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547216365; bh=4stqkj2j/0Rl9oP6ZCWB6uVhGHEVfsFocRqvqhbK9PA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=I6FqHEyGB7BQJ3Rc79I3iAu8Nm49xMw3RKVTZumjRQATZvayUAbbfcmCtUgc4bHHq Xzn0bSZNucls+JCl69xuh/CHA+tm4DgUa9fSFJpNLyIepW3CzOsQY3LGXBy+eJPHZo DRWsneS49aOHtn2CxC0LgHeZsh1EHyg/JcypM0P0= 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 4.4 46/88] spi: bcm2835: Fix race on DMA termination Date: Fri, 11 Jan 2019 15:08:15 +0100 Message-Id: <20190111131052.955380354@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190111131045.137499039@linuxfoundation.org> References: <20190111131045.137499039@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: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.4-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);