From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753457AbYKXUTO (ORCPT ); Mon, 24 Nov 2008 15:19:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750876AbYKXUS6 (ORCPT ); Mon, 24 Nov 2008 15:18:58 -0500 Received: from ug-out-1314.google.com ([66.249.92.170]:26990 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750812AbYKXUS5 (ORCPT ); Mon, 24 Nov 2008 15:18:57 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:in-reply-to:references:x-mailer :mime-version:content-type:content-transfer-encoding:sender; b=M4zwU9pT2K2sy//rEH/MMHunqC6EjJEKJ9E9WaxP4aO/KqpQauaQXmVpUxuEHiKnSW o7JEENhYGTEkKOl7AJFPpACz3ODl6ae+urcDvqvY+TXN4tCQhwetuBAW1/OglAZslD67 2TotwDumPk06l11nAUkzRJ0R66omaC9yioGfY= Date: Mon, 24 Nov 2008 22:18:49 +0200 From: Pekka Paalanen To: Ingo Molnar Cc: Steven Rostedt , linux-kernel , fweisbec@gmail.com Subject: Re: [PATCH 1/2] mmiotrace: fix buffer overrun detection Message-ID: <20081124221849.33c91bcf@daedalus.pq.iki.fi> In-Reply-To: <20081123193413.GB2794@elte.hu> References: <20081123154148.04e0851a@daedalus.pq.iki.fi> <20081123212430.4f6700e9@daedalus.pq.iki.fi> <20081123193413.GB2794@elte.hu> X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.11; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 23 Nov 2008 20:34:13 +0100 Ingo Molnar wrote: > Sure - applied them to tip/tracing/urgent: > > fb91ee6: tracing, doc: update mmiotrace documentation > 7ee1768: x86, mmiotrace: fix buffer overrun detection > > Does this make mmiotrace fully functional in .28 ? Oh right, the busylooping bug when echoing into trace_marker, I already forgot about that, since I couldn't reproduce it. I guess there's nothing to do, until someone finds a way to reproduce it. I could speculate about buffer wrap-around issues or such, but that requires some serious code reviewing. Btw. C-c'ing didn't interrupt the shell while spinning. The spinning ended when I switched the tracer or disabled it, IIRC. (This is related to 2.6.28-rc6.) On Sun, 23 Nov 2008, Pekka Paalanen wrote: > There's also another issue, but I am not sure how to reproduce it. > The symptom is, that > echo whatever > /debug/tracing/trace_marker > gets stuck in a loop, bash eats 100% CPU: 10% user, 90% system. > I got that twice today, like this: after a fresh boot echoing 64, 200, > 70 to trace_entries, switching between nop and mmiotrace tracers, > echoing 0 or 1 to tracing_enabled, and running the testmmiotrace > module. At some point the user marker got stuck. > > But then I tried to do that a third time by repeating some usage > patterns I thought might trigger it, but it didn't happen. -- Pekka Paalanen http://www.iki.fi/pq/