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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 D3043C47096 for ; Thu, 3 Jun 2021 23:33:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B86DD6140A for ; Thu, 3 Jun 2021 23:33:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229697AbhFCXfE (ORCPT ); Thu, 3 Jun 2021 19:35:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:55352 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229576AbhFCXfE (ORCPT ); Thu, 3 Jun 2021 19:35:04 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id BF4A3613EC; Thu, 3 Jun 2021 23:33:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1622763198; bh=So/Sf7/cZhEArag08ooBK1hP2tN8nJTb7kgTgxq8+K0=; h=Date:From:To:Subject:From; b=iKNwfcc9gWSsuEennaF08nFxFDDPVGQ5UAclYzcKs8BN3rcGQ3nQCoWkLhzjd2CIa yLpnCZo/4B65ctNZ51tG7j6JnX61Y1VvbOy3gxdfCkwKKecBUtj+RVBLp5hDH7yUPM QBq9LjTHqpqSleICVdXyg+soKc5cRpTMLMb1MVTU= Date: Thu, 03 Jun 2021 16:33:18 -0700 From: akpm@linux-foundation.org To: aarcange@redhat.com, hughd@google.com, mm-commits@vger.kernel.org, peterx@redhat.com Subject: + mm-swap-fix-pte_same_as_swp-not-removing-uffd-wp-bit-when-compare.patch added to -mm tree Message-ID: <20210603233318.Nn-3UFmQf%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/swap: fix pte_same_as_swp() not removing uffd-wp bit when compare has been added to the -mm tree. Its filename is mm-swap-fix-pte_same_as_swp-not-removing-uffd-wp-bit-when-compare.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-swap-fix-pte_same_as_swp-not-removing-uffd-wp-bit-when-compare.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-swap-fix-pte_same_as_swp-not-removing-uffd-wp-bit-when-compare.patch 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Peter Xu Subject: mm/swap: fix pte_same_as_swp() not removing uffd-wp bit when compare I found it by pure code review, that pte_same_as_swp() of unuse_vma() didn't take uffd-wp bit into account when comparing ptes. pte_same_as_swp() returning false negative could cause failure to swapoff swap ptes that was wr-protected by userfaultfd. Link: https://lkml.kernel.org/r/20210603180546.9083-1-peterx@redhat.com Signed-off-by: Peter Xu Cc: Hugh Dickins Cc: Andrea Arcangeli Signed-off-by: Andrew Morton --- include/linux/swapops.h | 15 +++++++++++---- mm/swapfile.c | 2 +- 2 files changed, 12 insertions(+), 5 deletions(-) --- a/include/linux/swapops.h~mm-swap-fix-pte_same_as_swp-not-removing-uffd-wp-bit-when-compare +++ a/include/linux/swapops.h @@ -23,6 +23,16 @@ #define SWP_TYPE_SHIFT (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT) #define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1) +/* Clear all flags but only keep swp_entry_t related information */ +static inline pte_t pte_swp_clear_flags(pte_t pte) +{ + if (pte_swp_soft_dirty(pte)) + pte = pte_swp_clear_soft_dirty(pte); + if (pte_swp_uffd_wp(pte)) + pte = pte_swp_clear_uffd_wp(pte); + return pte; +} + /* * Store a type+offset into a swp_entry_t in an arch-independent format */ @@ -66,10 +76,7 @@ static inline swp_entry_t pte_to_swp_ent { swp_entry_t arch_entry; - if (pte_swp_soft_dirty(pte)) - pte = pte_swp_clear_soft_dirty(pte); - if (pte_swp_uffd_wp(pte)) - pte = pte_swp_clear_uffd_wp(pte); + pte = pte_swp_clear_flags(pte); arch_entry = __pte_to_swp_entry(pte); return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry)); } --- a/mm/swapfile.c~mm-swap-fix-pte_same_as_swp-not-removing-uffd-wp-bit-when-compare +++ a/mm/swapfile.c @@ -1887,7 +1887,7 @@ unsigned int count_swap_pages(int type, static inline int pte_same_as_swp(pte_t pte, pte_t swp_pte) { - return pte_same(pte_swp_clear_soft_dirty(pte), swp_pte); + return pte_same(pte_swp_clear_flags(pte), swp_pte); } /* _ Patches currently in -mm which might be from peterx@redhat.com are mm-gup_benchmark-support-threading.patch mm-gup-pack-has_pinned-in-mmf_has_pinned-fix.patch userfaultfd-selftests-use-user-mode-only.patch userfaultfd-selftests-remove-the-time-check-on-delayed-uffd.patch userfaultfd-selftests-dropping-verify-check-in-locking_thread.patch userfaultfd-selftests-only-dump-counts-if-mode-enabled.patch userfaultfd-selftests-unify-error-handling.patch mm-thp-simplify-copying-of-huge-zero-page-pmd-when-fork.patch mm-userfaultfd-fix-uffd-wp-special-cases-for-fork.patch mm-userfaultfd-fix-a-few-thp-pmd-missing-uffd-wp-bit.patch mm-userfaultfd-fail-uffd-wp-registeration-if-not-supported.patch mm-pagemap-export-uffd-wp-protection-information.patch userfaultfd-selftests-add-pagemap-uffd-wp-test.patch userfaultfd-selftests-reinitialize-test-context-in-each-test-fix.patch mm-swap-fix-pte_same_as_swp-not-removing-uffd-wp-bit-when-compare.patch