From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754596Ab1K1UF4 (ORCPT ); Mon, 28 Nov 2011 15:05:56 -0500 Received: from casper.infradead.org ([85.118.1.10]:59990 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751868Ab1K1UFz convert rfc822-to-8bit (ORCPT ); Mon, 28 Nov 2011 15:05:55 -0500 Message-ID: <1322510741.2921.169.camel@twins> Subject: Re: [PATCH 4/9] ftrace: Add enable/disable ftrace_ops control interface From: Peter Zijlstra To: Steven Rostedt Cc: Jiri Olsa , fweisbec@gmail.com, mingo@redhat.com, paulus@samba.org, acme@ghostprotocols.net, linux-kernel@vger.kernel.org Date: Mon, 28 Nov 2011 21:05:41 +0100 In-Reply-To: <1322510552.2921.167.camel@twins> References: <1322417074-5834-1-git-send-email-jolsa@redhat.com> <1322417074-5834-5-git-send-email-jolsa@redhat.com> <1322508398.17003.9.camel@frodo> <1322510552.2921.167.camel@twins> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Mailer: Evolution 3.2.1- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2011-11-28 at 21:02 +0100, Peter Zijlstra wrote: > On Mon, 2011-11-28 at 14:26 -0500, Steven Rostedt wrote: > > > > Are jump labels safe in NMI context yet? If not, this will need to wait > > till we make it so. > > I don't think they are, we currently very much rely on that > stop_machine() crap. NMIs can go straight through that. > > I think you can make it work with the stop_machine()-less approach, > because then the NMI will trap on the INT3 which will wait for > completion, sync and resume the NMI. Note that this of course precludes ever using jump_labels from do_int3 handlers ;-)