From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754091Ab1A0Kbi (ORCPT ); Thu, 27 Jan 2011 05:31:38 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:54785 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753872Ab1A0Kbh convert rfc822-to-8bit (ORCPT ); Thu, 27 Jan 2011 05:31:37 -0500 Subject: Re: Q: perf_install_in_context/perf_event_enable are racy? From: Peter Zijlstra To: Oleg Nesterov Cc: Frederic Weisbecker , Ingo Molnar , Alan Stern , Arnaldo Carvalho de Melo , Paul Mackerras , Prasad , Roland McGrath , linux-kernel@vger.kernel.org In-Reply-To: <20110126213317.GA7403@redhat.com> References: <1295617185.28776.273.camel@laptop> <20110121142616.GA31165@redhat.com> <1295622304.28776.293.camel@laptop> <20110121204014.GA2870@nowhere> <20110124114234.GA12166@redhat.com> <20110126175322.GA28617@redhat.com> <20110126184957.GA32578@redhat.com> <1296068731.15234.6.camel@laptop> <1296070383.15234.10.camel@laptop> <20110126211931.GA6778@redhat.com> <20110126213317.GA7403@redhat.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Thu, 27 Jan 2011 11:32:17 +0100 Message-ID: <1296124337.15234.71.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2011-01-26 at 22:33 +0100, Oleg Nesterov wrote: > > This is what I had in mind initially but I didn't dare to add the > new member into rq, it is only needed for perf. Right, but its a weakness in the task_oncpu_function_call() implementation, wouldn't any user run into this problem eventually?