Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754141AbaJGPKu (ORCPT ); Tue, 7 Oct 2014 11:10:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:21251 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752462AbaJGPKq (ORCPT ); Tue, 7 Oct 2014 11:10:46 -0400 Date: Tue, 7 Oct 2014 12:10:35 -0300 From: Arnaldo Carvalho de Melo To: Stephane Eranian Cc: Namhyung Kim , LKML , Jiri Olsa , Peter Zijlstra , "mingo@elte.hu" , David Ahern Subject: Re: [PATCH v2] perf tools: fix off-by-one error in maps Message-ID: <20141007151035.GC2256@redhat.com> References: <20141006083532.GA4850@quad> <8761fwh1nc.fsf@sejong.aot.lge.com> <20141007140050.GB2256@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.20 (2009-12-10) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Tue, Oct 07, 2014 at 04:17:41PM +0200, Stephane Eranian escreveu: > On Tue, Oct 7, 2014 at 4:00 PM, Arnaldo Carvalho de Melo > wrote: > > Em Tue, Oct 07, 2014 at 02:47:19PM +0900, Namhyung Kim escreveu: > >> On Mon, 6 Oct 2014 10:35:32 +0200, Stephane Eranian wrote: > >> > This patch fixes off-by-one errors in the management of maps. > >> > A map is defined by start address and length as implemented by map__new(): > > > >> > map__init(map, type, start, start + len, pgoff, dso); > > > >> > map->start = addr; > >> > map->end = end; > > > >> > Consequently, the actual address range is ]start; end[ > >> > map->end is the first byte outside the range. This patch > >> > fixes two bugs where upper bound checking was off-by-one. > > > >> > In V2, we fix map_groups__fixup_overlappings() some more > >> > where map->start was off-by-one as reported by Jiri. > > > >> It seems we also need to fix maps__find(): > > > >> diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c > >> index b7090596ac50..107a8c90785b 100644 > >> --- a/tools/perf/util/map.c > >> +++ b/tools/perf/util/map.c > >> @@ -752,7 +752,7 @@ struct map *maps__find(struct rb_root *maps, u64 ip) > >> m = rb_entry(parent, struct map, rb_node); > >> if (ip < m->start) > >> p = &(*p)->rb_left; > >> - else if (ip > m->end) > >> + else if (ip >= m->end) > >> p = &(*p)->rb_right; > >> else > >> return m; > > > > I keep thinking that this change is making things unclear. > > > > I.e. the _start_ of a map (map->start) is _in_ the map, and the _end_ > > of a map (map->end) is _in_ the map as well. > > > > if (addr > m->end) > > > > is shorter than: > > > > if (addr >= m->end) > > > > "start" and "end" should have the same rule applied, i.e. if one is in, > > the other is in as well. > > > It is okay but then we need to be consistent all across. This is not > the case today. > I mentioned the cases I ran into. Ok, and provided a patch doing the way I thought was confusing, now its my turn to use that info and come up with a patch, ok, will do that. - Arnaldo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/