linux-kernel - Re: [PATCH v2] perf tools: fix off-by-one error in maps

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Date:	Tue, 7 Oct 2014 10:40:56 +0200
From:	Stephane Eranian <eranian@...gle.com>
To:	Namhyung Kim <namhyung@...nel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>, Jiri Olsa <jolsa@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	"mingo@...e.hu" <mingo@...e.hu>, David Ahern <dsahern@...il.com>
Subject: Re: [PATCH v2] perf tools: fix off-by-one error in maps

On Tue, Oct 7, 2014 at 7:47 AM, Namhyung Kim <namhyung@...nel.org> wrote:
> Hi Stephane,
>
> 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;
>
> Thanks,
> Namhyung
>
Yep, missing that one too. Hope there aren't any others....
Thanks.
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