From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753256Ab1K1QTX (ORCPT ); Mon, 28 Nov 2011 11:19:23 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124]:53361 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753075Ab1K1QTW (ORCPT ); Mon, 28 Nov 2011 11:19:22 -0500 X-Authority-Analysis: v=2.0 cv=QqvcLCOd c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=ajV93-eAzdgA:10 a=5SG0PmZfjMsA:10 a=IkcTkHD0fZMA:10 a=meVymXHHAAAA:8 a=20KFwNOVAAAA:8 a=15bDEA6I8iNRf3S8aq4A:9 a=mwUCi62oQvL9hUXDF1YA:7 a=QEXdDO2ut3YA:10 a=jeBq3FmKZ4MA:10 a=jEp0ucaQiEUA:10 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Subject: Re: [PATCH 1/9] trace: Fix uninitialized variable compiler warning From: Steven Rostedt To: Jiri Olsa Cc: fweisbec@gmail.com, mingo@redhat.com, paulus@samba.org, acme@ghostprotocols.net, linux-kernel@vger.kernel.org In-Reply-To: <1322417074-5834-2-git-send-email-jolsa@redhat.com> References: <1322417074-5834-1-git-send-email-jolsa@redhat.com> <1322417074-5834-2-git-send-email-jolsa@redhat.com> Content-Type: text/plain; charset="UTF-8" Date: Mon, 28 Nov 2011 11:19:18 -0500 Message-ID: <1322497158.17003.2.camel@frodo> Mime-Version: 1.0 X-Mailer: Evolution 2.32.3 (2.32.3-1.fc14) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Nacked-by: Steven Rostedt -- 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;