Arnaldo, On Mon, Oct 6, 2014 at 5:18 PM, Arnaldo Carvalho de Melo <[email protected]> wrote: > 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? > map->start = start; map->end = start + len;
Thus map->end is the first byte after the end. > 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); Yeah, that is the alternative. But are you sure this is the only place where a map is initialized. And this is not really C like. > > no? Isn't that clearer, i.e. to keep the semantics of 'end'? > Yeah, it all depends on what you meant by end: last byte or first byte after. But then everything needs to be consistent. That is what I am trying to fix in this patch. > - Arnaldo > >> fixes two bugs where upper bounds were off-by-one. >> >> Signed-off-by: Stephane Eranian <[email protected]> >> >> 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); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
