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=-7.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 AFE2DC433EF for ; Fri, 24 Sep 2021 00:16:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 91567604DA for ; Fri, 24 Sep 2021 00:16:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243594AbhIXAR7 (ORCPT ); Thu, 23 Sep 2021 20:17:59 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:43744 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232143AbhIXAR5 (ORCPT ); Thu, 23 Sep 2021 20:17:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1632442584; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=bcJHGrbVrok/puPN7U+j5l98fkTL9q1bHJVrXWV2gUI=; b=O9ThL9A81lLU1YtL4IwDhF+5I61cMfzuKIh+X7k4p3wr3F4XEyjy/36ISt0n2trpn4yJhg 235mFlAfe25FlIZsoYxaD5JzCX2ZoJ5j3m+DkgwESTPcjG4PgTy2NQGAfmNIUOkvqttKoA yrAMquQNzOtI9cvsDp3/U5yeOTuYHwQ= Received: from mail-qk1-f199.google.com (mail-qk1-f199.google.com [209.85.222.199]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-565-8CihHDGaOmGktXY1lITw0A-1; Thu, 23 Sep 2021 20:16:22 -0400 X-MC-Unique: 8CihHDGaOmGktXY1lITw0A-1 Received: by mail-qk1-f199.google.com with SMTP id bi14-20020a05620a318e00b00432f0915dd6so29061473qkb.6 for ; Thu, 23 Sep 2021 17:16:22 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=bcJHGrbVrok/puPN7U+j5l98fkTL9q1bHJVrXWV2gUI=; b=6WabV2bmJDyeZ+f/Fpdh3InpE1bmSgJNpS4Kw5uGn9cEzJ7GQ+YD/1239WzH8IlcA4 SlGpiPR3619IIzTNWYi3wndgfnmwzL8tZQ68p0RwPiWw6CrKl+NvK0HX1zz2eHSGtLA0 vZG+XRkLM6PZIVC/3KYJEn32kIRnRLOdzr2B9wEnY/PMV8nzjINJsCyX93rddcwZXe16 cmm/z2djDJzYkGhKTD7nRlzjfmLMINW+M9ckQCRqtuWMZpFTDAunzrdw34JHOmIZRpkf 9m6bLKPpA1sEFY5waEvZO08pQgsIPHXL3ZQ1MK8ycsJORLyDFNKaV0/8PhI9X/m69YqM YM6Q== X-Gm-Message-State: AOAM533OXl1NWF8Bv9uA1rdoDHDS6RByt47dfzDdfE4IMUJy9oBbcvJI 5kwsGHTQTmlZfOsDSfflBTiZFt+wiUAQ+BGoB4kz7iUFsVailqmSuqzIyEV4Y68pTsx8HXNhyDd T1VjzXUFjrKYCUlHEALsx6lNx X-Received: by 2002:ad4:4671:: with SMTP id z17mr7540875qvv.62.1632442582378; Thu, 23 Sep 2021 17:16:22 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzt4VN3dyUV71vYtJqa+uT4n4219syJ2qIIsc4SgS9eeq/Vm275w4yivFfacM2Y2MzU13kKOQ== X-Received: by 2002:ad4:4671:: with SMTP id z17mr7540849qvv.62.1632442581978; Thu, 23 Sep 2021 17:16:21 -0700 (PDT) Received: from t490s ([2607:fea8:56a2:9100::d3ec]) by smtp.gmail.com with ESMTPSA id h4sm5098180qkp.86.2021.09.23.17.16.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Sep 2021 17:16:21 -0700 (PDT) Date: Thu, 23 Sep 2021 20:16:19 -0400 From: Peter Xu To: Li Wang Cc: Nadav Amit , Andrew Morton , linux-kernel , Linux-MM , linux-fsdevel@vger.kernel.org, Nadav Amit , Andrea Arcangeli , stable@vger.kernel.org Subject: Re: [PATCH] userfaultfd: fix a race between writeprotect and exit_mmap() Message-ID: References: <20210921200247.25749-1-namit@vmware.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 22, 2021 at 05:06:53PM +0800, Li Wang wrote: > Hi, Li, > > I confirmed this patch (applied on 5.14) gets rid of the below userfaultfd > test failure. > > # ./userfaultfd anon 16 2 > nr_pages: 4096, nr_pages_per_cpu: 256 > bounces: 1, mode: rnd read, userfaults: 313 missing > (51+34+37+26+41+28+15+20+16+12+13+7+10+2+0+1) 995 wp > (121+79+96+53+90+104+48+61+56+82+56+41+49+26+11+22) > bounces: 0, mode: read, userfaults: 64 missing > (15+8+10+6+5+2+4+3+3+1+4+0+0+2+0+1) 2157 wp > (223+274+189+141+116+132+203+153+143+126+110+114+101+66+42+24) > testing uffd-wp with pagemap (pgsize=4096): done > testing uffd-wp with pagemap (pgsize=2097152): done > testing UFFDIO_ZEROPAGE: done. > testing signal delivery: done. > testing events (fork, remap, remove): ERROR: nr 3933 memory corruption 0 1 > (errno=0, line=963) > ERROR: faulting process failed (errno=0, line=1117) Just to keep a record within this thread - my understanding is above issue is a separate issue from what Nadav has fixed. The other fix could be: https://lore.kernel.org/lkml/20210923232512.210092-1-peterx@redhat.com/ When verify with Nadav's patch, please check whether you have thp enabled globally: # echo always > /sys/kernel/mm/transparent_hugepage/enabled Thanks, -- Peter Xu