From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753368Ab1K1QZK (ORCPT ); Mon, 28 Nov 2011 11:25:10 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42789 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751823Ab1K1QZJ (ORCPT ); Mon, 28 Nov 2011 11:25:09 -0500 Date: Mon, 28 Nov 2011 17:25:01 +0100 From: Jiri Olsa To: Steven Rostedt Cc: fweisbec@gmail.com, mingo@redhat.com, paulus@samba.org, acme@ghostprotocols.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/9] trace: Fix uninitialized variable compiler warning Message-ID: <20111128162501.GE2201@m.brq.redhat.com> References: <1322417074-5834-1-git-send-email-jolsa@redhat.com> <1322417074-5834-2-git-send-email-jolsa@redhat.com> <1322497158.17003.2.camel@frodo> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1322497158.17003.2.camel@frodo> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 28, 2011 at 11:19:18AM -0500, Steven Rostedt wrote: > On Sun, 2011-11-27 at 19:04 +0100, Jiri Olsa wrote: > > Initialize page2 variable to make compiler happy. > > What compiler is this? Because this is a compiler bug. In fact, there's > no check for page2 being NULL, so if it is used uninitialized it will > crash the kernel. I don't like these "make the compiler shut up" fixes, > because honestly, changes like this hide bugs. [jolsa@krava1 ~]$ gcc --version gcc (GCC) 4.4.5 20110214 (Red Hat 4.4.5-6) > > Nacked-by: Steven Rostedt understood, np jirka > > -- Steve > > > > > Signed-off-by: Jiri Olsa > > --- > > kernel/trace/trace.c | 3 +-- > > 1 files changed, 1 insertions(+), 2 deletions(-) > > > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > > index 9e158cc..4a06862 100644 > > --- a/kernel/trace/trace.c > > +++ b/kernel/trace/trace.c > > @@ -3655,8 +3655,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, > > struct page *pages[2]; > > int nr_pages = 1; > > ssize_t written; > > - void *page1; > > - void *page2; > > + void *page1, *page2 = NULL; > > int offset; > > int size; > > int len; > >