From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758228AbZDPQsU (ORCPT ); Thu, 16 Apr 2009 12:48:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757464AbZDPQsF (ORCPT ); Thu, 16 Apr 2009 12:48:05 -0400 Received: from casper.infradead.org ([85.118.1.10]:36143 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756812AbZDPQsE (ORCPT ); Thu, 16 Apr 2009 12:48:04 -0400 Subject: Re: [PATCH 2/2] tracing/events/lockdep: move tracepoints within recursive protection From: Peter Zijlstra To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Thomas Gleixner , Frederic Weisbecker In-Reply-To: <20090416161746.831882528@goodmis.org> References: <20090416161543.199331330@goodmis.org> <20090416161746.831882528@goodmis.org> Content-Type: text/plain Date: Thu, 16 Apr 2009 18:47:49 +0200 Message-Id: <1239900469.23397.3128.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.26.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2009-04-16 at 12:15 -0400, Steven Rostedt wrote: > plain text document attachment > (0002-tracing-events-lockdep-move-tracepoints-within-recu.patch) > From: Steven Rostedt > > With the current location of the tracepoints in lockdep, the system > can hard lockup in minutes when the tracepoints are enabled. > > Moving the tracepoints outside inside the lockdep protection solves > the issue. NAK the idea is to eventually move lockdep on top of the tracepoints. The tracer should grow to be more robust and handle recursion itself. Its likely a case of the tracer using a spinlock or mutex in the tracepoint code. When I did the tracepoints I converted one such to a raw_spinlock_t in the trace_print code.