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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3992FC00140 for ; Thu, 11 Aug 2022 01:25:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230251AbiHKBZq (ORCPT ); Wed, 10 Aug 2022 21:25:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57856 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233506AbiHKBZo (ORCPT ); Wed, 10 Aug 2022 21:25:44 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B47AA65670 for ; Wed, 10 Aug 2022 18:25:43 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5A1B661199 for ; Thu, 11 Aug 2022 01:25:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A68CBC433D6; Thu, 11 Aug 2022 01:25:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1660181142; bh=jNe1WGqGYBnM1Hk6Ex7L3F0Om4Ar59E6AZRIHUlHvnU=; h=Date:To:From:Subject:From; b=GuqV0+Y40SOyKxCy2eUBMuObqvs44bI3/TjqrX+TDARmVxpfHtu4ClKuqUZDXluid RaryrMh4D0Q05Cpv+lM753uWPJ+ZsJ3WkDUBwLeMNNU3Pymb5eAWnd9jFqq9ay/Jl6 AdLbp4MPZztqj2Pa+lg4JgE/HP71jHGCIKgf8vkk= Date: Wed, 10 Aug 2022 18:25:41 -0700 To: mm-commits@vger.kernel.org, ying.huang@intel.com, vbabka@suse.cz, shy828301@gmail.com, khlebnikov@openvz.org, david@redhat.com, peterx@redhat.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-smaps-dont-access-young-dirty-bit-if-pte-unpresent.patch added to mm-hotfixes-unstable branch Message-Id: <20220811012542.A68CBC433D6@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/smaps: don't access young/dirty bit if pte unpresent has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-smaps-dont-access-young-dirty-bit-if-pte-unpresent.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-smaps-dont-access-young-dirty-bit-if-pte-unpresent.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Peter Xu Subject: mm/smaps: don't access young/dirty bit if pte unpresent Date: Fri, 5 Aug 2022 12:00:03 -0400 These bits should only be valid when the ptes are present. Introducing two booleans for it and set it to false when !pte_present() for both pte and pmd accountings. The bug is found during code reading and no real world issue reported, but logically such an error can cause incorrect readings for either smaps or smaps_rollup output on quite a few fields. For example, it could cause over-estimate on values like Shared_Dirty, Private_Dirty, Referenced. Or it could also cause under-estimate on values like LazyFree, Shared_Clean, Private_Clean. Link: https://lkml.kernel.org/r/20220805160003.58929-1-peterx@redhat.com Fixes: b1d4d9e0cbd0 ("proc/smaps: carefully handle migration entries") Fixes: c94b6923fa0a ("/proc/PID/smaps: Add PMD migration entry parsing") Signed-off-by: Peter Xu Reviewed-by: Vlastimil Babka Reviewed-by: David Hildenbrand Reviewed-by: Yang Shi Cc: Konstantin Khlebnikov Cc: Huang Ying Signed-off-by: Andrew Morton --- fs/proc/task_mmu.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) --- a/fs/proc/task_mmu.c~mm-smaps-dont-access-young-dirty-bit-if-pte-unpresent +++ a/fs/proc/task_mmu.c @@ -527,10 +527,12 @@ static void smaps_pte_entry(pte_t *pte, struct vm_area_struct *vma = walk->vma; bool locked = !!(vma->vm_flags & VM_LOCKED); struct page *page = NULL; - bool migration = false; + bool migration = false, young = false, dirty = false; if (pte_present(*pte)) { page = vm_normal_page(vma, addr, *pte); + young = pte_young(*pte); + dirty = pte_dirty(*pte); } else if (is_swap_pte(*pte)) { swp_entry_t swpent = pte_to_swp_entry(*pte); @@ -560,8 +562,7 @@ static void smaps_pte_entry(pte_t *pte, if (!page) return; - smaps_account(mss, page, false, pte_young(*pte), pte_dirty(*pte), - locked, migration); + smaps_account(mss, page, false, young, dirty, locked, migration); } #ifdef CONFIG_TRANSPARENT_HUGEPAGE @@ -572,11 +573,13 @@ static void smaps_pmd_entry(pmd_t *pmd, struct vm_area_struct *vma = walk->vma; bool locked = !!(vma->vm_flags & VM_LOCKED); struct page *page = NULL; - bool migration = false; + bool migration = false, young = false, dirty = false; if (pmd_present(*pmd)) { /* FOLL_DUMP will return -EFAULT on huge zero page */ page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP); + young = pmd_young(*pmd); + dirty = pmd_dirty(*pmd); } else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) { swp_entry_t entry = pmd_to_swp_entry(*pmd); @@ -596,8 +599,7 @@ static void smaps_pmd_entry(pmd_t *pmd, else mss->file_thp += HPAGE_PMD_SIZE; - smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd), - locked, migration); + smaps_account(mss, page, true, young, dirty, locked, migration); } #else static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, _ Patches currently in -mm which might be from peterx@redhat.com are mm-smaps-dont-access-young-dirty-bit-if-pte-unpresent.patch