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 8F09EC43217 for ; Tue, 8 Nov 2022 23:58:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229949AbiKHX6c (ORCPT ); Tue, 8 Nov 2022 18:58:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51254 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229926AbiKHX6R (ORCPT ); Tue, 8 Nov 2022 18:58:17 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 57806606A1; Tue, 8 Nov 2022 15:58:16 -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 D3CC5617E4; Tue, 8 Nov 2022 23:58:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 32AE2C43470; Tue, 8 Nov 2022 23:58:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1667951895; bh=Rhokdn+5ejET0d+ZjL2KZQYSQALDc+3DCu8V18KSs4o=; h=Date:To:From:Subject:From; b=Mn4wYFf7HorFsjSqOc5dUY/gPrfed3vvpfOShe6NmrXfsJnqzZoytKjwgr/sKTWtf ReHLRuFC7YjIc3mD3msmc9AeAn9ZVvf41KNA0M6vHDY1QOkMRsx/6MAlvXKJhWFtuf 3aZpNbIAyaEc9f/4MWQb9R8DaoMth1Y/4z06tJV8= Date: Tue, 08 Nov 2022 15:58:14 -0800 To: mm-commits@vger.kernel.org, willy@infradead.org, stable@vger.kernel.org, hughd@google.com, axelrasmussen@google.com, aarcange@redhat.com, peterx@redhat.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-shmem-use-page_mapping-to-detect-page-cache-for-uffd-continue.patch removed from -mm tree Message-Id: <20221108235815.32AE2C43470@smtp.kernel.org> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The quilt patch titled Subject: mm/shmem: use page_mapping() to detect page cache for uffd continue has been removed from the -mm tree. Its filename was mm-shmem-use-page_mapping-to-detect-page-cache-for-uffd-continue.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/shmem: use page_mapping() to detect page cache for uffd continue Date: Wed, 2 Nov 2022 14:41:52 -0400 mfill_atomic_install_pte() checks page->mapping to detect whether one page is used in the page cache. However as pointed out by Matthew, the page can logically be a tail page rather than always the head in the case of uffd minor mode with UFFDIO_CONTINUE. It means we could wrongly install one pte with shmem thp tail page assuming it's an anonymous page. It's not that clear even for anonymous page, since normally anonymous pages also have page->mapping being setup with the anon vma. It's safe here only because the only such caller to mfill_atomic_install_pte() is always passing in a newly allocated page (mcopy_atomic_pte()), whose page->mapping is not yet setup. However that's not extremely obvious either. For either of above, use page_mapping() instead. Link: https://lkml.kernel.org/r/Y2K+y7wnhC4vbnP2@x1n Fixes: 153132571f02 ("userfaultfd/shmem: support UFFDIO_CONTINUE for shmem") Signed-off-by: Peter Xu Reported-by: Matthew Wilcox Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Axel Rasmussen Cc: Signed-off-by: Andrew Morton --- mm/userfaultfd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/userfaultfd.c~mm-shmem-use-page_mapping-to-detect-page-cache-for-uffd-continue +++ a/mm/userfaultfd.c @@ -64,7 +64,7 @@ int mfill_atomic_install_pte(struct mm_s pte_t _dst_pte, *dst_pte; bool writable = dst_vma->vm_flags & VM_WRITE; bool vm_shared = dst_vma->vm_flags & VM_SHARED; - bool page_in_cache = page->mapping; + bool page_in_cache = page_mapping(page); spinlock_t *ptl; struct inode *inode; pgoff_t offset, max_off; _ Patches currently in -mm which might be from peterx@redhat.com are selftests-vm-use-memfd-for-uffd-hugetlb-tests.patch selftests-vm-use-memfd-for-hugetlb-madvise-test.patch selftests-vm-use-memfd-for-hugepage-mremap-test.patch selftests-vm-drop-mnt-point-for-hugetlb-in-run_vmtestssh.patch mm-hugetlb-unify-clearing-of-restorereserve-for-private-pages.patch revert-mm-uffd-fix-warning-without-pte_marker_uffd_wp-compiled-in.patch mm-always-compile-in-pte-markers.patch mm-use-pte-markers-for-swap-errors.patch