From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756337Ab2GYQME (ORCPT ); Wed, 25 Jul 2012 12:12:04 -0400 Received: from mail-wg0-f44.google.com ([74.125.82.44]:56869 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753266Ab2GYQMA (ORCPT ); Wed, 25 Jul 2012 12:12:00 -0400 Date: Wed, 25 Jul 2012 18:11:53 +0200 From: Frederic Weisbecker To: Jiri Olsa Cc: acme@redhat.com, a.p.zijlstra@chello.nl, mingo@elte.hu, paulus@samba.org, cjashfor@linux.vnet.ibm.com, eranian@google.com, gorcunov@openvz.org, tzanussi@gmail.com, mhiramat@redhat.com, robert.richter@amd.com, fche@redhat.com, linux-kernel@vger.kernel.org, masami.hiramatsu.pt@hitachi.com, drepper@gmail.com, asharma@fb.com, benjamin.redelings@nescent.org Subject: Re: [PATCH 03/17] perf, x86: Add copy_from_user_nmi_nochk for best effort copy Message-ID: <20120725161150.GA1173@somewhere.redhat.com> References: <1342959280-5361-1-git-send-email-jolsa@redhat.com> <1342959280-5361-4-git-send-email-jolsa@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1342959280-5361-4-git-send-email-jolsa@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 22, 2012 at 02:14:26PM +0200, Jiri Olsa wrote: > Adding copy_from_user_nmi_nochk that provides the best effort > copy regardless the requesting size crossing the task boundary. > > This is going to be useful for stack dump we need in post > DWARF CFI based unwind, where we have predefined size of > the user stack to dump, and we need to store the most of > the requested dump size, regardless this size is crossing > the task boundary. What does that imply when we cross this limit? Are we still in the task stack?