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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 ADE87C4332B for ; Fri, 20 Mar 2020 13:49:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 871FF20739 for ; Fri, 20 Mar 2020 13:49:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727295AbgCTNtV (ORCPT ); Fri, 20 Mar 2020 09:49:21 -0400 Received: from mga18.intel.com ([134.134.136.126]:61578 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727145AbgCTNtV (ORCPT ); Fri, 20 Mar 2020 09:49:21 -0400 IronPort-SDR: 0H5ZmHhu5ZMmrCuxWlDy9P48iO8L2+0Z2IBEcyfV9Fqfw2oENczXLcNLEZ8Lg5DlrmKgqkP1uI Fh0ZigJKKuVQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Mar 2020 06:49:20 -0700 IronPort-SDR: sx8ITNZSnTwMSq0Hf11ksubXWWL+gSxYwn3+ZlxE2Xk3nIRX2yipZAer6kDd320RKO3JbYmLJG XLeN3VLsdtBQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,284,1580803200"; d="scan'208";a="237234433" Received: from che5-mobl.ccr.corp.intel.com (HELO [10.254.213.15]) ([10.254.213.15]) by fmsmga007.fm.intel.com with ESMTP; 20 Mar 2020 06:49:18 -0700 Cc: baolu.lu@linux.intel.com, Raj Ashok , Yi Liu Subject: Re: [PATCH 2/3] iommu/vt-d: Fix mm reference leak To: Jacob Pan , LKML , iommu@lists.linux-foundation.org, Joerg Roedel , David Woodhouse References: <1584678751-43169-1-git-send-email-jacob.jun.pan@linux.intel.com> <1584678751-43169-3-git-send-email-jacob.jun.pan@linux.intel.com> From: Lu Baolu Message-ID: <75592c19-309f-2626-68c9-1e74232be28e@linux.intel.com> Date: Fri, 20 Mar 2020 21:49:17 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <1584678751-43169-3-git-send-email-jacob.jun.pan@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/3/20 12:32, Jacob Pan wrote: > Move canonical address check before mmget_not_zero() to avoid mm > reference leak. > > Fixes: 9d8c3af31607 ("iommu/vt-d: IOMMU Page Request needs to check if > address is canonical.") > > Signed-off-by: Jacob Pan Acked-by: Lu Baolu Best regards, baolu > --- > drivers/iommu/intel-svm.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c > index 1483f1845762..56253c59ca10 100644 > --- a/drivers/iommu/intel-svm.c > +++ b/drivers/iommu/intel-svm.c > @@ -861,14 +861,15 @@ static irqreturn_t prq_event_thread(int irq, void *d) > * any faults on kernel addresses. */ > if (!svm->mm) > goto bad_req; > - /* If the mm is already defunct, don't handle faults. */ > - if (!mmget_not_zero(svm->mm)) > - goto bad_req; > > /* If address is not canonical, return invalid response */ > if (!is_canonical_address(address)) > goto bad_req; > > + /* If the mm is already defunct, don't handle faults. */ > + if (!mmget_not_zero(svm->mm)) > + goto bad_req; > + > down_read(&svm->mm->mmap_sem); > vma = find_extend_vma(svm->mm, address); > if (!vma || address < vma->vm_start) >