From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752893Ab0EQOTm (ORCPT ); Mon, 17 May 2010 10:19:42 -0400 Received: from casper.infradead.org ([85.118.1.10]:48209 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751878Ab0EQOTk (ORCPT ); Mon, 17 May 2010 10:19:40 -0400 Date: Mon, 17 May 2010 11:19:10 -0300 From: Arnaldo Carvalho de Melo To: Stephane Eranian Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@elte.hu, paulus@samba.org, davem@davemloft.net, fweisbec@gmail.com, perfmon2-devel@lists.sf.net, eranian@gmail.com Subject: Re: [PATCH] perf: fix bug mismatch with -c option definition Message-ID: <20100517141910.GA14367@ghostprotocols.net> References: <4bf11ae9.e88cd80a.06b0.ffffa8e3@mx.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4bf11ae9.e88cd80a.06b0.ffffa8e3@mx.google.com> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.20 (2009-08-17) X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Mon, May 17, 2010 at 12:04:01PM +0200, Stephane Eranian escreveu: > The -c option defines the user requested sampling period. It was implemented > using an unsigned int variable but the type of the option was OPT_LONG. Thus, > the option parser was overwriting memory belonging to other variables, namely > the mmap_pages leading to a zero page sampling buffer. The bug was exposed > only when compiling at -O0, probably because the compiler was padding > variables at higher optimization levels. Well spotted! > This patch fixes this problem by declaring user_interval as u64. This also > avoids wrap-around issues for large period on 32-bit systems. > > Signed-off-by: Stephane Eranian > -- > tools/perf/builtin-record.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index 0f467cf..78f64cc 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -33,8 +33,8 @@ enum write_mode_t { > > static int *fd[MAX_NR_CPUS][MAX_COUNTERS]; > > -static unsigned int user_interval = UINT_MAX; > -static long default_interval = 0; > +static u64 user_interval = ULLONG_MAX; > +static u64 default_interval = 0; The parsing code uses this for OPT_LONG: case OPTION_LONG: if (unset) { *(long *)opt->value = 0; return 0; } if (opt->flags & PARSE_OPT_OPTARG && !p->opt) { *(long *)opt->value = opt->defval; return 0; } if (get_arg(p, opt, flags, &arg)) return -1; *(long *)opt->value = strtol(arg, (char **)&s, 10); So I think we should augment the parsing code to have OPTION_ULONG, and, for handling u64, OPTION_ULLONG. I'll add that and then modify your patch to use it. - Arnaldo