From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f70.google.com (mail-wm0-f70.google.com [74.125.82.70]) by kanga.kvack.org (Postfix) with ESMTP id B521B6B000C for ; Wed, 20 Jun 2018 11:24:37 -0400 (EDT) Received: by mail-wm0-f70.google.com with SMTP id g78-v6so32803wmg.9 for ; Wed, 20 Jun 2018 08:24:37 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id t12-v6sor1375243wrp.50.2018.06.20.08.24.36 for (Google Transport Security); Wed, 20 Jun 2018 08:24:36 -0700 (PDT) From: Andrey Konovalov Subject: [PATCH v4 4/7] mm, arm64: untag user addresses in mm/gup.c Date: Wed, 20 Jun 2018 17:24:23 +0200 Message-Id: <1203c510e5c34e97e5940688df075d69429e94de.1529507994.git.andreyknvl@google.com> In-Reply-To: References: Sender: owner-linux-mm@kvack.org List-ID: To: Catalin Marinas , Will Deacon , Mark Rutland , Robin Murphy , Al Viro , Andrey Konovalov , Kees Cook , Kate Stewart , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Shuah Khan , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Chintan Pandya mm/gup.c provides a kernel interface that accepts user addresses and manipulates user pages directly (for example get_user_pages, that is used by the futex syscall). Here we also need to handle the case of tagged user pointers. Add untagging to gup.c functions that use user pointers for vma lookup. Signed-off-by: Andrey Konovalov --- mm/gup.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/gup.c b/mm/gup.c index b70d7ba7cc13..5bb351c91989 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -666,6 +666,8 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, if (!nr_pages) return 0; + start = untagged_addr(start); + VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET)); /* @@ -820,6 +822,8 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm, struct vm_area_struct *vma; int ret, major = 0; + address = untagged_addr(address); + if (unlocked) fault_flags |= FAULT_FLAG_ALLOW_RETRY; -- 2.18.0.rc1.244.gcf134e6275-goog