From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1344077-1526937830-2-12120405377280792004 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.248, MAILING_LIST_MULTI -1, RCVD_IN_DNSWL_HI -5, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' 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=fm2; t= 1526937829; b=Ik9yJBaipvDYl5eioQccZnAqBxxeuhQy/sc9XBeQQM/BTxWFXS jFZPA8LSrzC4iTSwpbxI7gWdHrhFoSpwlWWadOIHUJm+AyCC4ktxyw+gs2bR5EM7 tlb1c8ZzcdmnFo9H2t0f8KixAXNavlgdUv6gOpIjYljGNNlAAT96XCt35IzS6vPK aAj02A64eN/18hZdnzEnB+7SGDQ8L+WmROMSjdLis0UFZrIrWHs6YG3Rg2b9PYjB c4WRszEqLFfQQBLqE7/XHN/gazTXabfgIaqwRG1sygT/Gm8WXqgnTB/TVAdiw2/z K7+jTkvneyqqoIxxTwCNIUa5iVsMYu9R7d0Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=fm2; t=1526937829; bh=n/FZbBKjge0osJuVpTmORqbreB1jIY klAniZg+cQnjo=; b=jtTyHxN291FJbZdzXluIkb0k7xp5cxY/6a870RPof6OlDl E/bTRvnIBmbF0Ve1jlNPfA1fBdttkkMc+OeylI+ld8MrxIkUT4z5Zo0zK7sZXHAs t4jkyJTp0eBXs3ub0CkPFu4sBR+E1FJETti6jUVs24CEAPH1++TC7d3M9dl83dWt DgIBzd51jhPGtm3kp8LMP2AAnD9Al6nm4xygVrvIRB65Xodtov4lpivNb5ke1SN3 DP526YNoO+kXi5Bp3UjD+kTZIhP5XmUdeg8JLFlALenOn3ZOHWc+/sCUpyfAAuMc rmlsi8UdS82aquiVQ/9b66yNRx7jedFgFGGmEIng== ARC-Authentication-Results: i=1; mx3.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=kernel.org header.i=@kernel.org header.b=W0S9xrDF x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=default; dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.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=fail; x-cm=none score=0; 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=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx3.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=kernel.org header.i=@kernel.org header.b=W0S9xrDF x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=default; dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.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=fail; x-cm=none score=0; 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=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfD1gBz6f9vY+8MYb7uJq2GbdTKj0GD8ze3xLxcGRYBnhNiauz8YO1smH3qQ+O4mdiJHzK+/3Hxuwz7hBCjd4oYfZAT7oUL/d8+AdUcfGuoODYkSmqqJS j1Wq9E/ewxvW0TTLs8okZy9kgH59k66sSNB97prMMyTGARws4E7woV+3znRMuxV00Kk5VoEPhGkOj79A3pTFH4oRZlIbvcKzcBaj157dA8tAMCqI6+sghmWf X-CM-Analysis: v=2.3 cv=Tq3Iegfh c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=IkcTkHD0fZMA:10 a=VUJBJC2UJ8kA:10 a=yPCof4ZbAAAA:8 a=VwQbUJbxAAAA:8 a=QyXUC8HyAAAA:8 a=iox4zFpeAAAA:8 a=Z4Rwk6OoAAAA:8 a=R_Myd5XaAAAA:8 a=pGLkceISAAAA:8 a=ag1SF4gXAAAA:8 a=xHgKhLCoyhETZ0cQsJcA:9 a=phLPpX9aZRDPyI6O:21 a=kLrLtPfyZfhS22hT:21 a=QEXdDO2ut3YA:10 a=AjGcO6oz07-iQ99wixmX:22 a=WzC6qhA0u3u7Ye7llzcV:22 a=HkZW87K1Qel5hWWM3VKY:22 a=L2g4Dz8VuBQ37YGmWQah:22 a=Yupwre4RP9_Eg_Bd0iYG:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752133AbeEUVXp (ORCPT ); Mon, 21 May 2018 17:23:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:38532 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932170AbeEUVXl (ORCPT ); Mon, 21 May 2018 17:23:41 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pavel Tatashin , Michal Hocko , Andrew Morton , Steven Sistare , Daniel Jordan , Mel Gorman , Fengguang Wu , Dennis Zhou , Linus Torvalds Subject: [PATCH 4.16 038/110] mm: dont allow deferred pages with NEED_PER_CPU_KM Date: Mon, 21 May 2018 23:11:35 +0200 Message-Id: <20180521210507.196316358@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180521210503.823249477@linuxfoundation.org> References: <20180521210503.823249477@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pavel Tatashin commit ab1e8d8960b68f54af42b6484b5950bd13a4054b upstream. It is unsafe to do virtual to physical translations before mm_init() is called if struct page is needed in order to determine the memory section number (see SECTION_IN_PAGE_FLAGS). This is because only in mm_init() we initialize struct pages for all the allocated memory when deferred struct pages are used. My recent fix in commit c9e97a1997 ("mm: initialize pages on demand during boot") exposed this problem, because it greatly reduced number of pages that are initialized before mm_init(), but the problem existed even before my fix, as Fengguang Wu found. Below is a more detailed explanation of the problem. We initialize struct pages in four places: 1. Early in boot a small set of struct pages is initialized to fill the first section, and lower zones. 2. During mm_init() we initialize "struct pages" for all the memory that is allocated, i.e reserved in memblock. 3. Using on-demand logic when pages are allocated after mm_init call (when memblock is finished) 4. After smp_init() when the rest free deferred pages are initialized. The problem occurs if we try to do va to phys translation of a memory between steps 1 and 2. Because we have not yet initialized struct pages for all the reserved pages, it is inherently unsafe to do va to phys if the translation itself requires access of "struct page" as in case of this combination: CONFIG_SPARSE && !CONFIG_SPARSE_VMEMMAP The following path exposes the problem: start_kernel() trap_init() setup_cpu_entry_areas() setup_cpu_entry_area(cpu) get_cpu_gdt_paddr(cpu) per_cpu_ptr_to_phys(addr) pcpu_addr_to_page(addr) virt_to_page(addr) pfn_to_page(__pa(addr) >> PAGE_SHIFT) We disable this path by not allowing NEED_PER_CPU_KM with deferred struct pages feature. The problems are discussed in these threads: http://lkml.kernel.org/r/20180418135300.inazvpxjxowogyge@wfg-t540p.sh.intel.com http://lkml.kernel.org/r/20180419013128.iurzouiqxvcnpbvz@wfg-t540p.sh.intel.com http://lkml.kernel.org/r/20180426202619.2768-1-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180515175124.1770-1-pasha.tatashin@oracle.com Fixes: 3a80a7fa7989 ("mm: meminit: initialise a subset of struct pages if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set") Signed-off-by: Pavel Tatashin Acked-by: Michal Hocko Reviewed-by: Andrew Morton Cc: Steven Sistare Cc: Daniel Jordan Cc: Mel Gorman Cc: Fengguang Wu Cc: Dennis Zhou Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/Kconfig | 1 + 1 file changed, 1 insertion(+) --- a/mm/Kconfig +++ b/mm/Kconfig @@ -644,6 +644,7 @@ config DEFERRED_STRUCT_PAGE_INIT default n depends on NO_BOOTMEM depends on !FLATMEM + depends on !NEED_PER_CPU_KM help Ordinarily all struct pages are initialised during early boot in a single thread. On very large machines this can take a considerable