From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3262611-1519918177-2-6748842856473841604 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='us-ascii' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1519918176; b=Bv4jbN78iInSgsWb1eW0AR3C9GXPgLmsqrcouUjK18H58vm Mg3700mvVCB85k2v4vagj+e+gpsQRqjLpcSJx28QVnXaF2whXYr5RKv/40m75U4E o1E3rDkKLEFpIOgYm/C5PxVUOHjMOgQHLzNkuq3b45lmpNOP8qROXjxTSGic7/dp 9dQbhdSJCed46d7oS1osRpTk0fzO2JWJxbyt49TRDwShK8qaynNMy8Cle5EXnFv8 vuiFjQo/9dMeF036A9rnQw2Pn5fv0zo80Xbxs16EqJb7zyl+4tEupB/R4p62WG3e t7rdGKR3Xfl8pOssltKc+2eVouy9MIbLEgltZNA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to:sender :list-id; s=arctest; t=1519918176; bh=83Lgn/9WlYEvUmIaqMttycgVtf fJu+MoKyq5PgBbLkg=; b=dXDh5CS3sYtNlcCGUJ7+pqqfxRmnG2yxJhF2qeZxN4 br/GGVGs7O5D8ospIeFpk0F/iI/edltmA65x7XGoQCeL6kAghZL5tHW0nOWn83Wl ndWhExj3qt9R0NuzYRUeOin24IitM0SqetK5KbnrRkZeJzHrrBY1NcLnqtKIRkJ8 qyiqstfTyzLNPsen5codKKL/yIIGXPEmcvIEtkzsEiwawusJXGfOJmSoNIp1Yodt cYb6jFs9+c5Z59bqSFFYjH3rFnk3fqw9HgxaBsMAiivAgOI002E2mFWrTnLi7Db0 eQmdZfgf8cJIdo/5K8qFNXSuTPdEGXZ1cyAVWxUKe9Yg== ARC-Authentication-Results: i=1; mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=kernel.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=orgdomain_pass; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=kernel.org header.result=pass header_is_org_domain=yes Authentication-Results: mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=kernel.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=orgdomain_pass; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=kernel.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1032184AbeCAP2v (ORCPT ); Thu, 1 Mar 2018 10:28:51 -0500 Received: from mx2.suse.de ([195.135.220.15]:40309 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031984AbeCAP1b (ORCPT ); Thu, 1 Mar 2018 10:27:31 -0500 Date: Thu, 1 Mar 2018 16:27:29 +0100 From: Michal Hocko To: Daniel Vacek Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Vlastimil Babka , Mel Gorman , Pavel Tatashin , Paul Burton , stable@vger.kernel.org Subject: Re: [PATCH] mm/page_alloc: fix memmap_init_zone pageblock alignment Message-ID: <20180301152729.GM15057@dhcp22.suse.cz> References: <1519908465-12328-1-git-send-email-neelx@redhat.com> <20180301131033.GH15057@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.3 (2018-01-21) Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Thu 01-03-18 16:09:35, Daniel Vacek wrote: [...] > $ grep 7b7ff000 /proc/iomem > 7b7ff000-7b7fffff : System RAM [...] > After commit b92df1de5d28 machine eventually crashes with: > > BUG at mm/page_alloc.c:1913 > > > VM_BUG_ON(page_zone(start_page) != page_zone(end_page)); This is an important information that should be in the changelog. > >From registers and stack I digged start_page points to > ffffe31d01ed8000 (note that this is > page ffffe31d01edffc0 aligned to pageblock) and I can see this in memory dump: > > crash> kmem -p 77fff000 78000000 7b5ff000 7b600000 7b7fe000 7b7ff000 > 7b800000 7ffff000 80000000 > PAGE PHYSICAL MAPPING INDEX CNT FLAGS > ffffe31d01e00000 78000000 0 0 0 0 > ffffe31d01ed7fc0 7b5ff000 0 0 0 0 > ffffe31d01ed8000 7b600000 0 0 0 0 <<<< note Are those ranges covered by the System RAM as well? > that nodeid and zonenr are encoded in top bits of page flags which are > not initialized here, hence the crash :-( > ffffe31d01edff80 7b7fe000 0 0 0 0 > ffffe31d01edffc0 7b7ff000 0 0 1 1fffff00000000 > ffffe31d01ee0000 7b800000 0 0 1 1fffff00000000 > ffffe31d01ffffc0 7ffff000 0 0 1 1fffff00000000 It is still not clear why not to do the alignment in memblock_next_valid_pfn rahter than its caller. -- Michal Hocko SUSE Labs