From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754075Ab1AJNtK (ORCPT ); Mon, 10 Jan 2011 08:49:10 -0500 Received: from casper.infradead.org ([85.118.1.10]:35285 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753715Ab1AJNtI convert rfc822-to-8bit (ORCPT ); Mon, 10 Jan 2011 08:49:08 -0500 Subject: Re: [tip:perf/urgent] tracing: Include module.h in define_trace.h From: Peter Zijlstra To: linux-kernel@vger.kernel.org, mingo@redhat.com, hpa@zytor.com, rostedt@goodmis.org, srostedt@redhat.com, tglx@linutronix.de Cc: linux-tip-commits@vger.kernel.org In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Mon, 10 Jan 2011 14:49:37 +0100 Message-ID: <1294667377.11896.3.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 Sun, 2011-01-09 at 21:09 +0000, tip-bot for Steven Rostedt wrote: > Commit-ID: 3a9f987b3141f086de27832514aad9f50a53f754 > Gitweb: http://git.kernel.org/tip/3a9f987b3141f086de27832514aad9f50a53f754 > Author: Steven Rostedt > AuthorDate: Fri, 7 Jan 2011 15:40:10 -0500 > Committer: Steven Rostedt > CommitDate: Fri, 7 Jan 2011 15:44:56 -0500 > > tracing: Include module.h in define_trace.h > > While doing some developing, Peter Zijlstra and I have found > that if a CREATE_TRACE_POINTS include is done before module.h > is included, it can break the build. > > We have been lucky so far that this has not broke the build > since module.h is included in almost everything. > > Reported-by: Peter Zijlstra > Signed-off-by: Steven Rostedt > --- > include/trace/define_trace.h | 10 ++++++++++ > 1 files changed, 10 insertions(+), 0 deletions(-) > > diff --git a/include/trace/define_trace.h b/include/trace/define_trace.h > index b0b4eb2..da39b22 100644 > --- a/include/trace/define_trace.h > +++ b/include/trace/define_trace.h > @@ -21,6 +21,16 @@ > #undef CREATE_TRACE_POINTS > > #include > +/* > + * module.h includes tracepoints, and because ftrace.h > + * pulls in module.h: > + * trace/ftrace.h -> linux/ftrace_event.h -> linux/perf_event.h -> > + * linux/ftrace.h -> linux/module.h > + * we must include module.h here before we play with any of > + * the TRACE_EVENT() macros, otherwise the tracepoints included > + * by module.h may break the build. > + */ > +#include > > #undef TRACE_EVENT > #define TRACE_EVENT(name, proto, args, tstruct, assign, print) \ After I got everything building on that tree I was working on, the above was found to compile but not to link, since it makes every: #define CREATE_TRACE_POINTS #include site also create the trace/event/module.h tracepoints, thus confusing the linker with tons of duplicate symbols. The below patch makes things compile and link: --- include/trace/define_trace.h | 23 +++++++++++++---------- 1 files changed, 13 insertions(+), 10 deletions(-) diff --git a/include/trace/define_trace.h b/include/trace/define_trace.h index da39b22..9ebd0d3 100644 --- a/include/trace/define_trace.h +++ b/include/trace/define_trace.h @@ -21,16 +21,6 @@ #undef CREATE_TRACE_POINTS #include -/* - * module.h includes tracepoints, and because ftrace.h - * pulls in module.h: - * trace/ftrace.h -> linux/ftrace_event.h -> linux/perf_event.h -> - * linux/ftrace.h -> linux/module.h - * we must include module.h here before we play with any of - * the TRACE_EVENT() macros, otherwise the tracepoints included - * by module.h may break the build. - */ -#include #undef TRACE_EVENT #define TRACE_EVENT(name, proto, args, tstruct, assign, print) \ @@ -120,4 +110,17 @@ /* We may be processing more files */ #define CREATE_TRACE_POINTS +#else /* CREATE_TRACE_POINTS */ + +/* + * module.h includes tracepoints, and because ftrace.h + * pulls in module.h: + * trace/ftrace.h -> linux/ftrace_event.h -> linux/perf_event.h -> + * linux/ftrace.h -> linux/module.h + * we must include module.h here before we play with any of + * the TRACE_EVENT() macros, otherwise the tracepoints included + * by module.h may break the build. + */ +#include + #endif /* CREATE_TRACE_POINTS */