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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FROM_LOCAL_DIGITS,FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 9ED00C48BCF for ; Thu, 10 Jun 2021 02:21:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 78AEB613BC for ; Thu, 10 Jun 2021 02:21:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229770AbhFJCXY (ORCPT ); Wed, 9 Jun 2021 22:23:24 -0400 Received: from zg8tmty1ljiyny4xntqumjca.icoremail.net ([165.227.154.27]:37060 "HELO zg8tmty1ljiyny4xntqumjca.icoremail.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S229507AbhFJCXX (ORCPT ); Wed, 9 Jun 2021 22:23:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fudan.edu.cn; s=dkim; h=Received:Date:From:To:Cc:Subject: In-Reply-To:References:Content-Transfer-Encoding:Content-Type: MIME-Version:Message-ID; bh=NMsSgl6f+0/76cM6TWJIRwVGyQWYDV2Tj3+p XgGcVjw=; b=h0DdnxmDGdxo/ZvlIym9A/BSoYA8FvRFABsDpIC8PpAroL2Fg8Q7 eMnqA0rb9qKSRA0+qUfiTrQuALWbYnYgGcy0NpfWsvH25n66Ow/yXHrH5ZI9ZyxF tYYPBkrc22ILJ7++iGriysV4XdC8KFb8NJ42oEyjuZlrvPZUGRe3aIg= Received: by ajax-webmail-app2 (Coremail) ; Thu, 10 Jun 2021 10:20:24 +0800 (GMT+08:00) X-Originating-IP: [10.162.161.90] Date: Thu, 10 Jun 2021 10:20:24 +0800 (GMT+08:00) X-CM-HeaderCharset: UTF-8 From: "Xiyu Yang" <19210240158@fudan.edu.cn> To: "Robin Murphy" Cc: "Will Deacon" , "Joerg Roedel" , "Nicolin Chen" , "Bjorn Andersson" , "Krishna Reddy" , "Jordan Crouse" , "Sai Prakash Ranjan" , linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, yuanxzhang@fudan.edu.cn, "Xin Tan" Subject: Re: Re: [PATCH] iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails X-Priority: 3 X-Mailer: Coremail Webmail Server Version XT3.0.8 dev build 20200917(8294e55f) Copyright (c) 2002-2021 www.mailtech.cn fudan.edu.cn In-Reply-To: References: <1623245709-11123-1-git-send-email-xiyuyang19@fudan.edu.cn> X-SendMailWithSms: false Content-Transfer-Encoding: 7bit X-CM-CTRLDATA: ZmoaFmZvb3Rlcl90eHQ9Mzk1ODoxMA== Content-Type: text/plain; charset=UTF-8 MIME-Version: 1.0 Message-ID: <3da0a67a.3d4d.179f3b87d02.Coremail.19210240158@fudan.edu.cn> X-Coremail-Locale: en_US X-CM-TRANSID: XQUFCgCHTGvodsFgpJpUAw--.21437W X-CM-SenderInfo: irzsiiysuqikmy6i3vldqovvfxof0/1tbiAQwIAVKp4t+ptgACsf X-Coremail-Antispam: 1Ur529EdanIXcx71UUUUU7IcSsGvfJ3iIAIbVAYjsxI4VWxJw CS07vEb4IE77IF4wCS07vE1I0E4x80FVAKz4kxMIAIbVAFxVCaYxvI4VCIwcAKzIAtYxBI daVFxhVjvjDU= Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thanks for your advice, I'll send a v2 patch soon. > -----Original Messages----- > From: "Robin Murphy" > Sent Time: 2021-06-09 22:12:11 (Wednesday) > To: "Xiyu Yang" , "Will Deacon" , "Joerg Roedel" , "Nicolin Chen" , "Bjorn Andersson" , "Krishna Reddy" , "Jordan Crouse" , "Sai Prakash Ranjan" , linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org > Cc: yuanxzhang@fudan.edu.cn, "Xin Tan" > Subject: Re: [PATCH] iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails > > On 2021-06-09 14:35, Xiyu Yang wrote: > > arm_smmu_rpm_get() invokes pm_runtime_get_sync(), which increases the > > refcount of the "smmu" even though the return value is less than 0. > > > > The reference counting issue happens in some error handling paths of > > arm_smmu_rpm_get() in its caller functions. When arm_smmu_rpm_get() > > fails, the caller functions forget to decrease the refcount of "smmu" > > increased by arm_smmu_rpm_get(), causing a refcount leak. > > > > Fix this issue by calling arm_smmu_rpm_put() or jumping to the "rpm_put" > > label when arm_smmu_rpm_get() fails. > > If only there was some kind of helper function which could encapsulate > the correct expected behaviour in a single place... > > In fact with the new pm_runtime_resume_and_get() API I think these two > patches boil down to a one-line change. > > Thanks, > Robin. > > > Signed-off-by: Xiyu Yang > > Signed-off-by: Xin Tan > > --- > > drivers/iommu/arm/arm-smmu/arm-smmu.c | 13 +++++++++---- > > 1 file changed, 9 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c > > index 6f72c4d208ca..177ee54c5534 100644 > > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c > > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c > > @@ -840,7 +840,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) > > > > ret = arm_smmu_rpm_get(smmu); > > if (ret < 0) > > - return; > > + goto rpm_put; > > > > /* > > * Disable the context bank and free the page tables before freeing > > @@ -857,6 +857,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) > > free_io_pgtable_ops(smmu_domain->pgtbl_ops); > > __arm_smmu_free_bitmap(smmu->context_map, cfg->cbndx); > > > > +rpm_put: > > arm_smmu_rpm_put(smmu); > > } > > > > @@ -1153,7 +1154,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) > > > > ret = arm_smmu_rpm_get(smmu); > > if (ret < 0) > > - return ret; > > + goto rpm_put; > > > > /* Ensure that the domain is finalised */ > > ret = arm_smmu_init_domain_context(domain, smmu, dev); > > @@ -1404,7 +1405,7 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev) > > > > ret = arm_smmu_rpm_get(smmu); > > if (ret < 0) > > - goto out_cfg_free; > > + goto rpm_put; > > > > ret = arm_smmu_master_alloc_smes(dev); > > arm_smmu_rpm_put(smmu); > > @@ -1417,6 +1418,8 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev) > > > > return &smmu->iommu; > > > > +rpm_put: > > + arm_smmu_rpm_put(smmu); > > out_cfg_free: > > kfree(cfg); > > out_free: > > @@ -1438,8 +1441,10 @@ static void arm_smmu_release_device(struct device *dev) > > smmu = cfg->smmu; > > > > ret = arm_smmu_rpm_get(smmu); > > - if (ret < 0) > > + if (ret < 0) { > > + arm_smmu_rpm_put(smmu); > > return; > > + } > > > > arm_smmu_master_free_smes(cfg, fwspec); > > > >