From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f71.google.com (mail-wm0-f71.google.com [74.125.82.71]) by kanga.kvack.org (Postfix) with ESMTP id 028336B0010 for ; Fri, 25 May 2018 13:21:27 -0400 (EDT) Received: by mail-wm0-f71.google.com with SMTP id a16-v6so3947011wmg.9 for ; Fri, 25 May 2018 10:21:26 -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 b9-v6sor12353822wra.72.2018.05.25.10.21.25 for (Google Transport Security); Fri, 25 May 2018 10:21:25 -0700 (PDT) From: Andrey Konovalov Subject: [PATCH v3 4/6] mm, arm64: untag user addresses in mm/gup.c Date: Fri, 25 May 2018 19:21:14 +0200 Message-Id: <858608ce6ace4ebd71c0318d3d536e9d1918b613.1527268727.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" , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@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 541904a7c60f..5d0e9715bab7 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -650,6 +650,8 @@ 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)); /* @@ -804,6 +806,8 @@ 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; -- 2.17.0.921.gf22659ad46-goog