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 85927C11F66 for ; Thu, 1 Jul 2021 01:49:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7004B61468 for ; Thu, 1 Jul 2021 01:49:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238400AbhGABvh (ORCPT ); Wed, 30 Jun 2021 21:51:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:40966 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238384AbhGABvh (ORCPT ); Wed, 30 Jun 2021 21:51:37 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C0A4E61469; Thu, 1 Jul 2021 01:49:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1625104147; bh=zdOaIlOLdN22SKbBP9VrmQ4d6AMoLYE4qirfKewrXKc=; h=Date:From:To:Subject:In-Reply-To:From; b=Heowlqhpeb8YspTqqkVik2xtlG3jAr1W1DMbr2FeCAkITy3ypMv7+PAtBDPYs7OYQ b6wk2DifsuSMGhWvct+5uRPYwd0p1QB1ZsdY/pEiGZy1WKkjB6wCW8j6ipcfNvPJuk tonQMa/TmkQkdKYPoVXzQLX8i/RGCkkcfvPe7GBY= Date: Wed, 30 Jun 2021 18:49:06 -0700 From: Andrew Morton To: aarcange@redhat.com, akpm@linux-foundation.org, almasrymina@google.com, axelrasmussen@google.com, bgeffon@google.com, dgilbert@redhat.com, hughd@google.com, jglisse@redhat.com, joe@perches.com, kirill@shutemov.name, linux-mm@kvack.org, lokeshgidra@google.com, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, oupton@google.com, peterx@redhat.com, rppt@linux.vnet.ibm.com, sfr@canb.auug.org.au, shli@fb.com, shuah@kernel.org, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk, wangqing@vivo.com Subject: [patch 037/192] mm/userfaultfd: fail uffd-wp registration if not supported Message-ID: <20210701014906.8qOxw6Ozk%akpm@linux-foundation.org> In-Reply-To: <20210630184624.9ca1937310b0dd5ce66b30e7@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 From: Peter Xu Subject: mm/userfaultfd: fail uffd-wp registration if not supported We should fail uffd-wp registration immediately if the arch does not even have CONFIG_HAVE_ARCH_USERFAULTFD_WP defined. That'll block also relevant ioctls on e.g. UFFDIO_WRITEPROTECT because that'll check against VM_UFFD_WP, which can only be applied with a success registration. Remove the WP feature bit too for those archs when handling UFFDIO_API ioctl. Link: https://lkml.kernel.org/r/20210428225030.9708-5-peterx@redhat.com Signed-off-by: Peter Xu Cc: Alexander Viro Cc: Andrea Arcangeli Cc: Axel Rasmussen Cc: Brian Geffon Cc: "Dr . David Alan Gilbert" Cc: Hugh Dickins Cc: Jerome Glisse Cc: Joe Perches Cc: Kirill A. Shutemov Cc: Lokesh Gidra Cc: Mike Kravetz Cc: Mike Rapoport Cc: Mina Almasry Cc: Oliver Upton Cc: Shaohua Li Cc: Shuah Khan Cc: Stephen Rothwell Cc: Wang Qing Signed-off-by: Andrew Morton --- fs/userfaultfd.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/fs/userfaultfd.c~mm-userfaultfd-fail-uffd-wp-registeration-if-not-supported +++ a/fs/userfaultfd.c @@ -1304,8 +1304,12 @@ static int userfaultfd_register(struct u vm_flags = 0; if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MISSING) vm_flags |= VM_UFFD_MISSING; - if (uffdio_register.mode & UFFDIO_REGISTER_MODE_WP) + if (uffdio_register.mode & UFFDIO_REGISTER_MODE_WP) { +#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP + goto out; +#endif vm_flags |= VM_UFFD_WP; + } if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MINOR) { #ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR goto out; @@ -1943,6 +1947,9 @@ static int userfaultfd_api(struct userfa #ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR uffdio_api.features &= ~UFFD_FEATURE_MINOR_HUGETLBFS; #endif +#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP + uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP; +#endif uffdio_api.ioctls = UFFD_API_IOCTLS; ret = -EFAULT; if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api))) _