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=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 227A8C433EC for ; Mon, 20 Jul 2020 16:24:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E6AAA2073A for ; Mon, 20 Jul 2020 16:24:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595262241; bh=brtp9yHjy3ziQVxTsjjgYfS8uVlOTxN4qyMt/fPozVw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=X1L2zsywKVBFuGeNtl+fW9zALTDWEpnL75BSOunKO+Bddh1Jp+evuLTFY+mZ8bIna 78dNgL/hsqcuWce19qMCGGFBtgYGYy0uYOcJximusuB2uNkIRFObIbSitMiXkvdr5h XjLLoHENswk7KG187UamSASkaCadRle4q3IOkEzE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732845AbgGTQEa (ORCPT ); Mon, 20 Jul 2020 12:04:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:39212 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732834AbgGTQEX (ORCPT ); Mon, 20 Jul 2020 12:04:23 -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 4292A2064B; Mon, 20 Jul 2020 16:04:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595261062; bh=brtp9yHjy3ziQVxTsjjgYfS8uVlOTxN4qyMt/fPozVw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DOrIA4Z6uEULndJDGR7KYV+ajywV9gZUXslF3OMucS+5kzXyxVFrvFLX0rE+v7zvB GeuyIlp6u9I9FWCHB77V8em2M8Ih2EvwpfIpzcxV7+U6GFbIQIDFXmDvINATybiY8m OMrTybk/fvKFK9LCw3Cyb/lEqdl9nfHrzemluYSI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Krzysztof Kozlowski , Robin Gong , Vinod Koul Subject: [PATCH 5.4 194/215] dmaengine: mcf-edma: Fix NULL pointer exception in mcf_edma_tx_handler Date: Mon, 20 Jul 2020 17:37:56 +0200 Message-Id: <20200720152829.412085710@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200720152820.122442056@linuxfoundation.org> References: <20200720152820.122442056@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 From: Krzysztof Kozlowski commit 8995aa3d164ddd9200e6abcf25c449cf5298c858 upstream. On Toradex Colibri VF50 (Vybrid VF5xx) with fsl-edma driver NULL pointer exception happens occasionally on serial output initiated by login timeout. This was reproduced only if kernel was built with significant debugging options and EDMA driver is used with serial console. Issue looks like a race condition between interrupt handler fsl_edma_tx_handler() (called as a result of fsl_edma_xfer_desc()) and terminating the transfer with fsl_edma_terminate_all(). The fsl_edma_tx_handler() handles interrupt for a transfer with already freed edesc and idle==true. The mcf-edma driver shares design and lot of code with fsl-edma. It looks like being affected by same problem. Fix this pattern the same way as fix for fsl-edma driver. Fixes: e7a3ff92eaf1 ("dmaengine: fsl-edma: add ColdFire mcf5441x edma support") Cc: Signed-off-by: Krzysztof Kozlowski Reviewed-by: Robin Gong Link: https://lore.kernel.org/r/1591881665-25592-1-git-send-email-krzk@kernel.org Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- drivers/dma/mcf-edma.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/dma/mcf-edma.c +++ b/drivers/dma/mcf-edma.c @@ -35,6 +35,13 @@ static irqreturn_t mcf_edma_tx_handler(i mcf_chan = &mcf_edma->chans[ch]; spin_lock(&mcf_chan->vchan.lock); + + if (!mcf_chan->edesc) { + /* terminate_all called before */ + spin_unlock(&mcf_chan->vchan.lock); + continue; + } + if (!mcf_chan->edesc->iscyclic) { list_del(&mcf_chan->edesc->vdesc.node); vchan_cookie_complete(&mcf_chan->edesc->vdesc);