Messages in this thread | | | Date | Mon, 6 Oct 2014 12:18:23 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH] perf tools: fix off-by-one error in maps |
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Em Fri, Oct 03, 2014 at 12:47:07PM +0200, Stephane Eranian escreveu: > > 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__init() > { > 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
I thought map->end should be the end of the range, not something after the end, is that really the case?
I.e. the bug would be in that call to map__init, that should instead be:
map__init(map, type, start, start + len - 1, pgoff, dso);
no? Isn't that clearer, i.e. to keep the semantics of 'end'?
- Arnaldo
> fixes two bugs where upper bounds were off-by-one. > > Signed-off-by: Stephane Eranian <eranian@google.com> > > diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c > index b709059..9e2c71e 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, > @@ -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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