From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755310Ab3BKKPL (ORCPT ); Mon, 11 Feb 2013 05:15:11 -0500 Received: from us01smtp3.synopsys.com ([198.182.44.81]:59565 "EHLO hermes.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755131Ab3BKKPJ (ORCPT ); Mon, 11 Feb 2013 05:15:09 -0500 Message-ID: <5118C458.2070205@synopsys.com> Date: Mon, 11 Feb 2013 15:43:44 +0530 From: Vineet Gupta User-Agent: Mozilla/5.0 (X11; Linux i686; rv:16.0) Gecko/20121011 Thunderbird/16.0.1 MIME-Version: 1.0 To: Jonas Bonn CC: Arnd Bergmann , "linux-arch@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Al Viro Subject: Re: pt_regs leak into userspace (was Re: [PATCH v3 20/71] ARC: Signal handling) References: <1359024639-21915-1-git-send-email-vgupta@synopsys.com> <1359024639-21915-9-git-send-email-vgupta@synopsys.com> <51189D2F.4030000@synopsys.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.12.197.43] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 11 February 2013 03:06 PM, Jonas Bonn wrote: > On 11 February 2013 08:26, Vineet Gupta wrote: > >> The only downside of this patch is that userspace signal stack grows in size, >> since signal frame only cares about scratch regs (pt_regs), but has to accommodate >> unused placeholder for callee regs too by virtue of using user_regs_struct. > Is this really true? Don't setcontext and friends require that _all_ > the registers be part of sigcontext? But for an ABI - callee saved regs will anyhow be saved/restored even in setcontext case ! So collecting it for that purpose seems useless, or am I missing something here. -Vineet