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perf tools: fix off-by-one error in maps

PATCH New Stephane Eranian 1 participant 1 message Oct 7, 2014 perf events

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Stephane Eranian

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PATCH v3 1/1 perf tools: fix off-by-one error in maps

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.

In V3, we also fix:
- __map_groups__fixup_end()
- maps__find() as report by Namhyung

Signed-off-by Stephane Eranian <[email protected]>
---
 tools/perf/util/map.c    | 8 ++++----
 tools/perf/util/symbol.c | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)
tools/perf/util/map.c +4 -4
index b709059..2137c45 100644
@@ -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);

@@ -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;
tools/perf/util/symbol.c +1 -1
index be84f7a..c787a43 100644
@@ -207,7 +207,7 @@ void __map_groups__fixup_end(struct map_groups *mg, enum map_type type)
 	for (nd = rb_next(prevnd); nd; nd = rb_next(nd)) {
 		prev = curr;
 		curr = rb_entry(nd, struct map, rb_node);
-		prev->end = curr->start - 1;
+		prev->end = curr->start;
 	}
 
 	/*
Signature · 1 line
1.9.1