Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752251AbaLOKDQ (ORCPT ); Mon, 15 Dec 2014 05:03:16 -0500 Received: from mail-la0-f43.google.com ([209.85.215.43]:57792 "EHLO mail-la0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751690AbaLOKDN (ORCPT ); Mon, 15 Dec 2014 05:03:13 -0500 MIME-Version: 1.0 In-Reply-To: <1418575877-21488-1-git-send-email-mst@redhat.com> References: <1418575877-21488-1-git-send-email-mst@redhat.com> Date: Mon, 15 Dec 2014 18:03:10 +0800 Message-ID: Subject: Re: [PATCH 00/18] uaccess: fix sparse warning on get_user for bitwise types From: "LF.Tan" To: "Michael S. Tsirkin" Cc: "linux-kernel@vger.kernel.org" , Arnd Bergmann , Linux-Arch Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 15, 2014 at 12:51 AM, Michael S. Tsirkin wrote: > At the moment, if p and x are both tagged as bitwise types, > get_user(x, p) produces a sparse warning on many architectures. > This is because *p on these architectures is loaded into long > (typically using asm), then cast back to typeof(*p). > > When typeof(*p) is a bitwise type (which is uncommon), such a cast needs > __force, otherwise sparse produces a warning. > > Some architectures already have the __force tag, add it > where it's missing. > > Specificlly, vhost wants to read bitwise types from userspace using get_user. > At the moment this triggers sparse errors, since the value is passed through an > integer. > > For now, I worked around this by converting vhost code to access_ok + > __get_user, but that's not robust, I'd like to switch to get_user for 3.19. > > I tested this on x86 only so far. Since it's just adding __force, should be > trivially safe everywhere? > > Please review, and consider for 3.19. > > Who can merge this? Arnd? Hi Michael FYI, there is new arch (arch/nios2) in 3.19. Is your patchset include the fix for it? Thanks. Regards Ley Foon -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/