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 B34EEC38159 for ; Thu, 19 Jan 2023 01:03:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229866AbjASBCz (ORCPT ); Wed, 18 Jan 2023 20:02:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229483AbjASBCt (ORCPT ); Wed, 18 Jan 2023 20:02:49 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 08922683CF; Wed, 18 Jan 2023 17:02:48 -0800 (PST) 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 7C1CF61B08; Thu, 19 Jan 2023 01:02:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D5D6DC433D2; Thu, 19 Jan 2023 01:02:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1674090166; bh=uzD8Ka8JTx/epQ3MAVqfduaJNtunGYzsoPt7QvN+Bu4=; h=Date:To:From:Subject:From; b=d4Aqfv0xhM1k0oiB/z+r+KEzQYGvyNEyW9KWs1GYc4Mv9zJnSAyTHlU0l244f1VyZ Ub+CrX89j0xA2zDzfUTLDF+iZuCQa37i/UZ3um0jqSOx7VymOJp9Pn77sXmzqJJhPp CnLWtFtKyUgTmcVCSOF1XnohIoJ5fYt1IakICnmo= Date: Wed, 18 Jan 2023 17:02:46 -0800 To: mm-commits@vger.kernel.org, ying.huang@intel.com, stable@vger.kernel.org, pengfei.xu@intel.com, nadav.amit@gmail.com, linmiaohe@huawei.com, david@redhat.com, aarcange@redhat.com, peterx@redhat.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-uffd-fix-pte-marker-when-fork-without-fork-event.patch removed from -mm tree Message-Id: <20230119010246.D5D6DC433D2@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/uffd: fix pte marker when fork() without fork event has been removed from the -mm tree. Its filename was mm-uffd-fix-pte-marker-when-fork-without-fork-event.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/uffd: fix pte marker when fork() without fork event Date: Wed, 14 Dec 2022 15:04:52 -0500 Patch series "mm: Fixes on pte markers". Patch 1 resolves the syzkiller report from Pengfei. Patch 2 further harden pte markers when used with the recent swapin error markers. The major case is we should persist a swapin error marker after fork(), so child shouldn't read a corrupted page. This patch (of 2): When fork(), dst_vma is not guaranteed to have VM_UFFD_WP even if src may have it and has pte marker installed. The warning is improper along with the comment. The right thing is to inherit the pte marker when needed, or keep the dst pte empty. A vague guess is this happened by an accident when there's the prior patch to introduce src/dst vma into this helper during the uffd-wp feature got developed and I probably messed up in the rebase, since if we replace dst_vma with src_vma the warning & comment it all makes sense too. Hugetlb did exactly the right here (copy_hugetlb_page_range()). Fix the general path. Reproducer: https://github.com/xupengfe/syzkaller_logs/blob/main/221208_115556_copy_page_range/repro.c Bugzilla report: https://bugzilla.kernel.org/show_bug.cgi?id=216808 Link: https://lkml.kernel.org/r/20221214200453.1772655-1-peterx@redhat.com Link: https://lkml.kernel.org/r/20221214200453.1772655-2-peterx@redhat.com Fixes: c56d1b62cce8 ("mm/shmem: handle uffd-wp during fork()") Signed-off-by: Peter Xu Reported-by: Pengfei Xu Acked-by: David Hildenbrand Reviewed-by: Miaohe Lin Cc: Andrea Arcangeli Cc: "Huang, Ying" Cc: Nadav Amit Cc: # 5.19+ Signed-off-by: Andrew Morton --- mm/memory.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) --- a/mm/memory.c~mm-uffd-fix-pte-marker-when-fork-without-fork-event +++ a/mm/memory.c @@ -828,12 +828,8 @@ copy_nonpresent_pte(struct mm_struct *ds return -EBUSY; return -ENOENT; } else if (is_pte_marker_entry(entry)) { - /* - * We're copying the pgtable should only because dst_vma has - * uffd-wp enabled, do sanity check. - */ - WARN_ON_ONCE(!userfaultfd_wp(dst_vma)); - set_pte_at(dst_mm, addr, dst_pte, pte); + if (userfaultfd_wp(dst_vma)) + set_pte_at(dst_mm, addr, dst_pte, pte); return 0; } if (!userfaultfd_wp(dst_vma)) _ Patches currently in -mm which might be from peterx@redhat.com are selftests-vm-remove-__use_gnu-in-hugetlb-madvisec.patch mm-uffd-always-wr-protect-pte-in-ptepmd_mkuffd_wp.patch mm-mprotect-use-long-for-page-accountings-and-retval.patch mm-uffd-detect-pgtable-allocation-failures.patch mm-hugetlb-let-vma_offset_start-to-return-start.patch mm-hugetlb-dont-wait-for-migration-entry-during-follow-page.patch mm-hugetlb-document-huge_pte_offset-usage.patch mm-hugetlb-move-swap-entry-handling-into-vma-lock-when-faulted.patch mm-hugetlb-make-userfaultfd_huge_must_wait-safe-to-pmd-unshare.patch mm-hugetlb-make-hugetlb_follow_page_mask-safe-to-pmd-unshare.patch mm-hugetlb-make-follow_hugetlb_page-safe-to-pmd-unshare.patch mm-hugetlb-make-walk_hugetlb_range-safe-to-pmd-unshare.patch mm-hugetlb-introduce-hugetlb_walk.patch