Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757066Ab1FIHTL (ORCPT ); Thu, 9 Jun 2011 03:19:11 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:37658 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757045Ab1FIHTI (ORCPT ); Thu, 9 Jun 2011 03:19:08 -0400 Date: Thu, 9 Jun 2011 09:18:54 +0200 From: Ingo Molnar To: Robert Richter Cc: Peter Zijlstra , LKML , oprofile-list , Suravee Suthikulpanit , stable@kernel.org Subject: Re: [PATCH] oprofile, x86: Fix race in nmi handler while starting Message-ID: <20110609071854.GE20544@elte.hu> References: <1307465249-20055-1-git-send-email-robert.richter@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1307465249-20055-1-git-send-email-robert.richter@amd.com> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.3.1 -2.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 990 Lines: 25 * Robert Richter wrote: > In some rare cases, nmis are generated immediately after the nmi > handler of the cpu was started. This causes the counter not to be > enabled. Before enabling the nmi handlers we need to set variable > ctr_running first and make sure its value is written to memory. > > Also, the patch makes all existing barriers a memory barrier > instead of a compiler barrier only. Could we *PLEASE* just do the obvious and turn oprofile into a perf user on x86 too, like ARM already does? Two years down the line and there's zero progress in that area. We want to obsolete the Oprofile PMU bits on x86, the infrastructure duplication causes non-trivial problems like this one. Thanks, Ingo -- 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/