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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 8557AC64EB4 for ; Fri, 30 Nov 2018 10:07:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5775F20863 for ; Fri, 30 Nov 2018 10:07:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5775F20863 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=be4energy.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726870AbeK3VQd (ORCPT ); Fri, 30 Nov 2018 16:16:33 -0500 Received: from mail.be4energy.com ([217.6.180.170]:51617 "EHLO mail.be4energy.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726572AbeK3VQd (ORCPT ); Fri, 30 Nov 2018 16:16:33 -0500 Received: from linux-7rm0.localnet (172.16.135.185) by SVRDC01.be4energy.local (172.16.135.100) with Microsoft SMTP Server id 14.3.361.1; Fri, 30 Nov 2018 11:07:40 +0100 From: Mario Forner To: Richard Genoud CC: Ludovic Desroches , Dan Williams , Vinod Koul , Alexandre Belloni , Nicolas Ferre , Maxime Ripard , , , , , Subject: Re: [PATCH] dmaengine: at_hdmac: fix memory leak in at_dma_xlate() Date: Fri, 30 Nov 2018 11:07:39 +0100 Message-ID: <3059696.Xnxl6OxYbg@linux-7rm0> Organization: be4energy GmbH In-Reply-To: <20181127160635.11836-1-richard.genoud@gmail.com> References: <20181127160635.11836-1-richard.genoud@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Originating-IP: [172.16.135.185] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Dienstag, 27. November 2018, 17:06:34 CET schrieb Richard Genoud: > The leak was found when opening/closing a serial port a great number of > time, increasing kmalloc-32 in slabinfo. > > Each time the port was opened, dma_request_slave_channel() was called. > Then, in at_dma_xlate(), atslave was allocated with devm_kzalloc() and > never freed. (Well, it was free at module unload, but that's not what we > want). > So, here, kzalloc is more suited for the job since it has to be freed in > atc_free_chan_resources(). > > Cc: stable@vger.kernel.org > Fixes: bbe89c8e3d59 ("at_hdmac: move to generic DMA binding") > Reported-by: Mario Forner > Suggested-by: Alexandre Belloni > Acked-by: Alexandre Belloni > Signed-off-by: Richard Genoud After testing I installed an updated kernel on a production machine, which worked fine. The memory leak has been repaired successfully. There have been no adverse side-effects. Thank you for providing the patch. > --- > drivers/dma/at_hdmac.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c > index 7cbac6e8c113..1b7f0ca0d5cd 100644 > --- a/drivers/dma/at_hdmac.c > +++ b/drivers/dma/at_hdmac.c > @@ -1641,6 +1641,12 @@ static void atc_free_chan_resources(struct dma_chan *chan) > atchan->descs_allocated = 0; > atchan->status = 0; > > + /* > + * Free atslave allocated in at_dma_xlate() > + */ > + kfree(chan->private); > + chan->private = NULL; > + > dev_vdbg(chan2dev(chan), "free_chan_resources: done\n"); > } > > @@ -1675,7 +1681,7 @@ static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec, > dma_cap_zero(mask); > dma_cap_set(DMA_SLAVE, mask); > > - atslave = devm_kzalloc(&dmac_pdev->dev, sizeof(*atslave), GFP_KERNEL); > + atslave = kzalloc(sizeof(*atslave), GFP_KERNEL); > if (!atslave) > return NULL; > >