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

From: Arnaldo Carvalho de Melo
Date: Tue Oct 14 2014 - 15:04:30 EST


Em Tue, Oct 07, 2014 at 02:47:19PM +0900, Namhyung Kim escreveu:
> 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():


So I am getting this as an ack for Stephane's V2 patch and the patch
below as an extra patch, from you, acked by Stephane.

- Arnaldo

>
> 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
>
>
> >
> > Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
> > ---
> > tools/perf/util/map.c | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
> > index b709059..186418b 100644
> > --- a/tools/perf/util/map.c
> > +++ b/tools/perf/util/map.c
> > @@ -556,7 +556,7 @@ struct symbol *map_groups__find_symbol_by_name(struct map_groups *mg,
> >
> > int map_groups__find_ams(struct addr_map_symbol *ams, symbol_filter_t filter)
> > {
> > - if (ams->addr < ams->map->start || ams->addr > ams->map->end) {
> > + if (ams->addr < ams->map->start || ams->addr >= ams->map->end) {
> > if (ams->map->groups == NULL)
> > return -1;
> > ams->map = map_groups__find(ams->map->groups, ams->map->type,
> > @@ -664,7 +664,7 @@ int map_groups__fixup_overlappings(struct map_groups *mg, struct map *map,
> > goto move_map;
> > }
> >
> > - before->end = map->start - 1;
> > + before->end = map->start;
> > map_groups__insert(mg, before);
> > if (verbose >= 2)
> > map__fprintf(before, fp);
> > @@ -678,7 +678,7 @@ int map_groups__fixup_overlappings(struct map_groups *mg, struct map *map,
> > goto move_map;
> > }
> >
> > - after->start = map->end + 1;
> > + after->start = map->end;
> > map_groups__insert(mg, after);
> > if (verbose >= 2)
> > map__fprintf(after, fp);
--
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