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=-19.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 D8FB8C4338F for ; Tue, 24 Aug 2021 17:05:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB4A861B9F for ; Tue, 24 Aug 2021 17:05:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238623AbhHXRGg (ORCPT ); Tue, 24 Aug 2021 13:06:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:45820 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239287AbhHXRE2 (ORCPT ); Tue, 24 Aug 2021 13:04:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 393A1615E2; Tue, 24 Aug 2021 16:59:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629824366; bh=m6MWtSt77nDnHiKnoKPOb31isqXnEqjQVfdpnzdnvIc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hnxSFij6IHCe5hhb0M9DmDCFU9Vgh6J+1sA3DBhUjzhiIQY+2HFrr0U1UDYhRuW18 Mm8bKH4YkTom3dusu/pFq2NfLyc49w28IFtECcqOddeKCblJW/+C/ymXqCQ2otiZi0 ftn+8JnJM+SgSp9Rho3ycgrMfrCwAdFMIFk/nDqMCxur+b+e7lP4yF4UTW2nUtQ9jF 7i/iosX4PJPFFXuykKLtdvtXy4TBIQBOzM6FmFUkMLprGbJFN1Y3eEocgsBMNjvM8U P7Kw4bhYH9TWDGTlNJR6i2ui3mzQFaW/rdW48nhTmUD0hHV4hw71sxVrC7G1MPUVVu +HDcUwE8csZUQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Adrian Larumbe , Vinod Koul , Sasha Levin Subject: [PATCH 5.10 16/98] dmaengine: xilinx_dma: Fix read-after-free bug when terminating transfers Date: Tue, 24 Aug 2021 12:57:46 -0400 Message-Id: <20210824165908.709932-17-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210824165908.709932-1-sashal@kernel.org> References: <20210824165908.709932-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.10.61-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.10.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.10.61-rc1 X-KernelTest-Deadline: 2021-08-26T16:58+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Adrian Larumbe [ Upstream commit 7dd2dd4ff9f3abda601f22b9d01441a0869d20d7 ] When user calls dmaengine_terminate_sync, the driver will clean up any remaining descriptors for all the pending or active transfers that had previously been submitted. However, this might happen whilst the tasklet is invoking the DMA callback for the last finished transfer, so by the time it returns and takes over the channel's spinlock, the list of completed descriptors it was traversing is no longer valid. This leads to a read-after-free situation. Fix it by signalling whether a user-triggered termination has happened by means of a boolean variable. Signed-off-by: Adrian Larumbe Link: https://lore.kernel.org/r/20210706234338.7696-3-adrian.martinezlarumbe@imgtec.com Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin --- drivers/dma/xilinx/xilinx_dma.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c index 79777550a6ff..9ffdbeec436b 100644 --- a/drivers/dma/xilinx/xilinx_dma.c +++ b/drivers/dma/xilinx/xilinx_dma.c @@ -394,6 +394,7 @@ struct xilinx_dma_tx_descriptor { * @genlock: Support genlock mode * @err: Channel has errors * @idle: Check for channel idle + * @terminating: Check for channel being synchronized by user * @tasklet: Cleanup work after irq * @config: Device configuration info * @flush_on_fsync: Flush on Frame sync @@ -431,6 +432,7 @@ struct xilinx_dma_chan { bool genlock; bool err; bool idle; + bool terminating; struct tasklet_struct tasklet; struct xilinx_vdma_config config; bool flush_on_fsync; @@ -1049,6 +1051,13 @@ static void xilinx_dma_chan_desc_cleanup(struct xilinx_dma_chan *chan) /* Run any dependencies, then free the descriptor */ dma_run_dependencies(&desc->async_tx); xilinx_dma_free_tx_descriptor(chan, desc); + + /* + * While we ran a callback the user called a terminate function, + * which takes care of cleaning up any remaining descriptors + */ + if (chan->terminating) + break; } spin_unlock_irqrestore(&chan->lock, flags); @@ -1965,6 +1974,8 @@ static dma_cookie_t xilinx_dma_tx_submit(struct dma_async_tx_descriptor *tx) if (desc->cyclic) chan->cyclic = true; + chan->terminating = false; + spin_unlock_irqrestore(&chan->lock, flags); return cookie; @@ -2436,6 +2447,7 @@ static int xilinx_dma_terminate_all(struct dma_chan *dchan) xilinx_dma_chan_reset(chan); /* Remove and free all of the descriptors in the lists */ + chan->terminating = true; xilinx_dma_free_descriptors(chan); chan->idle = true; -- 2.30.2