Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757581Ab2EYRkx (ORCPT ); Fri, 25 May 2012 13:40:53 -0400 Received: from mga14.intel.com ([143.182.124.37]:19631 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751434Ab2EYRkv (ORCPT ); Fri, 25 May 2012 13:40:51 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="147867696" Message-ID: <4FBFC421.3020901@linux.intel.com> Date: Fri, 25 May 2012 10:40:49 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Steven Rostedt CC: Dave Jones , Linux Kernel , Frederic Weisbecker , Ingo Molnar , Andi Kleen Subject: Re: BUG - function tracing with breakpoints References: <20120524160146.GA6226@redhat.com> <1337876398.13348.178.camel@gandalf.stny.rr.com> <20120524172223.GA10689@redhat.com> <1337902816.13348.224.camel@gandalf.stny.rr.com> <4FBEC9E6.8040301@linux.intel.com> <1337909963.13348.232.camel@gandalf.stny.rr.com> <1337910106.13348.234.camel@gandalf.stny.rr.com> <1337956262.13348.257.camel@gandalf.stny.rr.com> <1337959746.13348.264.camel@gandalf.stny.rr.com> In-Reply-To: <1337959746.13348.264.camel@gandalf.stny.rr.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 796 Lines: 21 On 05/25/2012 08:29 AM, Steven Rostedt wrote: > > This would make sense for this bug, as if modifying_ftrace_code was not > seen by other CPUs, it wouldn't go into the ftrace_int3_handler() path. > That would cause this issue. But the bug remains after the smp_mb()'s > were put in place. Although it behaves a little differently not. Maybe > there's something else I missed? > Perhaps you should make the modifying_ftrace_code modification atomic... it seems odd to have it not be atomic when it is clearly accessed across CPUs that way. -hpa -- 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/