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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 017BCC47E49 for ; Wed, 23 Oct 2019 13:44:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CD08A21928 for ; Wed, 23 Oct 2019 13:44:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="NxHFS4h2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405793AbfJWNoR (ORCPT ); Wed, 23 Oct 2019 09:44:17 -0400 Received: from mail-lj1-f180.google.com ([209.85.208.180]:46709 "EHLO mail-lj1-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392056AbfJWNoR (ORCPT ); Wed, 23 Oct 2019 09:44:17 -0400 Received: by mail-lj1-f180.google.com with SMTP id d1so21135043ljl.13 for ; Wed, 23 Oct 2019 06:44:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=fVWT8LOX7hiMjzmwaVkkcwJWIfsHuA36zoSZSTB0yuM=; b=NxHFS4h2zxcr3PyzhLh0Qk9xOCqJL026hwR5FNmCyixHEVD0e4yCc909qhJLWtZeUZ H1qF87BDiynS9cV8CLEYWhoizZdJ3Tmnpc5iBaED04sqTeqtnbuuLJl/xAJmILJqMWaW syhtRcFRp1DlALraodSUrtNeJZjhhMc93jsvZ7ZWdMyajqhVxWJ88/8tmTjFAzHap9As 6GpHUUomwMjlnj8BcpEDjTuNFo4ifhGv4pBzOsexIWTFDInb1sJ6mWsimYwHtLvlh60S H0epGqYjqPxvO+jgcm94cGSjkzx9yE68irp9JNkAZbhL31WmM7c9gK1KVlQUnonTC0F0 pc5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=fVWT8LOX7hiMjzmwaVkkcwJWIfsHuA36zoSZSTB0yuM=; b=Hn8ahiyUcNDwc9IRhUHFpelC/j3FQcviccbSrrRtZbjQ4wParU+FlHQcgZNMVVzXuV bKGPNVhejx8L89vhFe7X/UyVaG6agcKpGVMx93L/hqoRBQd0lXnwvnkVUXyTFQePl40v AbU4QfspsINwgaxW0J5xqdrH5skkT311U5sZyl7I4ZrXTTc/cO6+R1tYKkiW1khenxdn SNETffSFzijKXxM4TILfl1nlTomGbLVzNuF3Z0xl+smo+4ojvwA3wv6bNSxKKWZc9oP3 22v7xUSjJt91EipdGr5G+sQi7kKT381xobTpKqcIEYuo2525fCrif2xDuEr2vfR2z3ld oeSA== X-Gm-Message-State: APjAAAVJDTTdRvjAmh5p+r98puu/jMzt2u6A5yAjdnZPbrOiQrkSKkWf pXkfJXRIoLBh23JJ0HzeYQd7hJi1 X-Google-Smtp-Source: APXvYqxJ14Zwj0CcAv5ywhBjFN4Mtan5pZ6k/oKrgQiJlZi0Sv2tbD/Q4jWuGGXpxXVVkCuT5qlJqQ== X-Received: by 2002:a05:651c:8b:: with SMTP id 11mr14588261ljq.100.1571838255226; Wed, 23 Oct 2019 06:44:15 -0700 (PDT) Received: from uranus.localdomain ([5.18.199.94]) by smtp.gmail.com with ESMTPSA id n11sm13123511lfd.88.2019.10.23.06.44.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Oct 2019 06:44:13 -0700 (PDT) Received: by uranus.localdomain (Postfix, from userid 1000) id 4C2A34610AC; Wed, 23 Oct 2019 16:44:13 +0300 (MSK) Date: Wed, 23 Oct 2019 16:44:13 +0300 From: Cyrill Gorcunov To: Thomas Gleixner Cc: LKML , Ingo Molnar , Peter Zijlstra , linux-mm@kvack.org, Catalin Marinas Subject: Re: [BUG -tip] kmemleak and stacktrace cause page faul Message-ID: <20191023134413.GI12121@uranus.lan> References: <20191019114421.GK9698@uranus.lan> <20191022142325.GD12121@uranus.lan> <20191022145619.GE12121@uranus.lan> <20191023133204.GH12121@uranus.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 23, 2019 at 03:38:40PM +0200, Thomas Gleixner wrote: > > > > > > [0,2,4,5,6,8,10,12] are guard pages so 0 is not that crappy at all > > > > Wait, Thomas, I might be wrong, but per-cpu is initialized to the pointer, > > the memory for this estack_pages has not yet been allocated, no? > > static const > struct estack_pages estack_pages[CEA_ESTACK_PAGES] ____cacheline_aligned = { > EPAGERANGE(DF), > EPAGERANGE(NMI), > EPAGERANGE(DB1), > EPAGERANGE(DB), > EPAGERANGE(MCE), > }; > > It's statically allocated. So it's available from the very beginning. Indeed, thanks! I happened to overlooked this moment. ... > And as I explained to you properly decoded the values _ARE_ correct and > make sense. Yes, just posted the diff itself to be sure. Thanks a huge for explanation, Thomas!