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 1E0EAC10F07 for ; Thu, 7 Dec 2023 00:13:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1441834AbjLGANT (ORCPT ); Wed, 6 Dec 2023 19:13:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1441852AbjLGANR (ORCPT ); Wed, 6 Dec 2023 19:13:17 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B24ED1 for ; Wed, 6 Dec 2023 16:13:23 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9905AC433CA; Thu, 7 Dec 2023 00:13:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1701908002; bh=Q89/B2Wd7CDV/OOh178wJC2rHiK/4ZzpxmMIcqh94NY=; h=Date:To:From:Subject:From; b=ILowlN8DIdPImMGOXC3XjX7JYUR7tW8Uef3MEGHimCy4S2lAzMUfXEug3cfvvbYB3 qTa05+qnO94qRb7WRgdeA7xX+5M1I7twFEj227ZYMUWhk0JOeKSai+S5M7lzmDEgkA DTHJuToKBZPEP0R6T0AD1IF/D+6WiAHUtmT7Mm9M= Date: Wed, 06 Dec 2023 16:13:22 -0800 To: mm-commits@vger.kernel.org, usama.anjum@collabora.com, david@redhat.com, avagin@gmail.com, peterx@redhat.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-pagemap-fix-ioctlpagemap_scan-on-vma-check.patch removed from -mm tree Message-Id: <20231207001322.9905AC433CA@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: mm/pagemap: fix ioctl(PAGEMAP_SCAN) on vma check has been removed from the -mm tree. Its filename was mm-pagemap-fix-ioctlpagemap_scan-on-vma-check.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Peter Xu Subject: mm/pagemap: fix ioctl(PAGEMAP_SCAN) on vma check Date: Thu, 16 Nov 2023 15:15:45 -0500 Patch series "mm/pagemap: A few fixes to the recent PAGEMAP_SCAN". This series should fix two known reports from syzbot on the new PAGEMAP_SCAN ioctl(): https://lore.kernel.org/all/000000000000b0e576060a30ee3b@google.com/ https://lore.kernel.org/all/000000000000773fa7060a31e2cc@google.com/ The 3rd patch is something I found when testing these patches. This patch (of 3): The new ioctl(PAGEMAP_SCAN) relies on vma wr-protect capability provided by userfault, however in the vma test it didn't explicitly require the vma to have wr-protect function enabled, even if PM_SCAN_WP_MATCHING flag is set. It means the pagemap code can now apply uffd-wp bit to a page in the vma even if not registered to userfaultfd at all. Then in whatever way as long as the pte got written and page fault resolved, we'll apply the write bit even if uffd-wp bit is set. We'll see a pte that has both UFFD_WP and WRITE bit set. Anything later that looks up the pte for uffd-wp bit will trigger the warning: WARNING: CPU: 1 PID: 5071 at arch/x86/include/asm/pgtable.h:403 pte_uffd_wp arch/x86/include/asm/pgtable.h:403 [inline] Fix it by doing proper check over the vma attributes when PM_SCAN_WP_MATCHING is specified. Link: https://lkml.kernel.org/r/20231116201547.536857-1-peterx@redhat.com Link: https://lkml.kernel.org/r/20231116201547.536857-2-peterx@redhat.com Fixes: 52526ca7fdb9 ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs") Signed-off-by: Peter Xu Reported-by: syzbot+e94c5aaf7890901ebf9b@syzkaller.appspotmail.com Reviewed-by: David Hildenbrand Reviewed-by: Andrei Vagin Reviewed-by: Muhammad Usama Anjum Signed-off-by: Andrew Morton --- fs/proc/task_mmu.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) --- a/fs/proc/task_mmu.c~mm-pagemap-fix-ioctlpagemap_scan-on-vma-check +++ a/fs/proc/task_mmu.c @@ -1982,15 +1982,31 @@ static int pagemap_scan_test_walk(unsign struct pagemap_scan_private *p = walk->private; struct vm_area_struct *vma = walk->vma; unsigned long vma_category = 0; + bool wp_allowed = userfaultfd_wp_async(vma) && + userfaultfd_wp_use_markers(vma); - if (userfaultfd_wp_async(vma) && userfaultfd_wp_use_markers(vma)) - vma_category |= PAGE_IS_WPALLOWED; - else if (p->arg.flags & PM_SCAN_CHECK_WPASYNC) - return -EPERM; + if (!wp_allowed) { + /* User requested explicit failure over wp-async capability */ + if (p->arg.flags & PM_SCAN_CHECK_WPASYNC) + return -EPERM; + /* + * User requires wr-protect, and allows silently skipping + * unsupported vmas. + */ + if (p->arg.flags & PM_SCAN_WP_MATCHING) + return 1; + /* + * Then the request doesn't involve wr-protects at all, + * fall through to the rest checks, and allow vma walk. + */ + } if (vma->vm_flags & VM_PFNMAP) return 1; + if (wp_allowed) + vma_category |= PAGE_IS_WPALLOWED; + if (!pagemap_scan_is_interesting_vma(vma_category, p)) return 1; _ Patches currently in -mm which might be from peterx@redhat.com are fs-kconfig-make-hugetlbfs-a-menuconfig.patch mm-gup-fix-follow_devmap_pd-on-page==null-handling.patch