perf tools: Check if a map is still in use when deleting it

index b57a027..c434e12 100644
@@ -59,6 +59,10 @@ static int perf_evsel__add_sample(struct perf_evsel *evsel,
 	    (al->sym == NULL ||
 	     strcmp(ann->sym_hist_filter, al->sym->name) != 0)) {
 		/* We're only interested in a symbol named sym_hist_filter */
+		/*
+		 * FIXME: why isn't this done in the symbol_filter when loading
+		 * the DSO?
+		 */
 		if (al->sym != NULL) {
 			rb_erase(&al->sym->rb_node,
 				 &al->map->dso->symbols[al->map->type]);

index 0905b07..4d3a92d 100644
@@ -225,6 +225,7 @@ struct map *map__new2(u64 start, struct dso *dso, enum map_type type)
 
 void map__delete(struct map *map)
 {
+	BUG_ON(!RB_EMPTY_NODE(&map->rb_node));
 	free(map);
 }
 

@@ -446,7 +447,7 @@ static void __maps__purge(struct maps *maps)
 		struct map *pos = rb_entry(next, struct map, rb_node);
 
 		next = rb_next(&pos->rb_node);
-		rb_erase(&pos->rb_node, root);
+		rb_erase_init(&pos->rb_node, root);
 		map__delete(pos);
 	}
 }

@@ -456,7 +457,7 @@ static void __maps__purge_removed_maps(struct maps *maps)
 	struct map *pos, *n;
 
 	list_for_each_entry_safe(pos, n, &maps->removed_maps, node) {
-		list_del(&pos->node);
+		list_del_init(&pos->node);
 		map__delete(pos);
 	}
 }

@@ -671,7 +672,7 @@ static int maps__fixup_overlappings(struct maps *maps, struct map *map, FILE *fp
 			map__fprintf(pos, fp);
 		}
 
-		rb_erase(&pos->rb_node, root);
+		rb_erase_init(&pos->rb_node, root);
 		/*
 		 * Now check if we need to create new maps for areas not
 		 * overlapped by the new map:

@@ -782,7 +783,7 @@ void maps__insert(struct maps *maps, struct map *map)
 
 static void __maps__remove(struct maps *maps, struct map *map)
 {
-	rb_erase(&map->rb_node, &maps->entries);
+	rb_erase_init(&map->rb_node, &maps->entries);
 }
 
 void maps__remove(struct maps *maps, struct map *map)

index 8aae8b6..743a9b3 100644
@@ -659,14 +659,14 @@ static int dso__split_kallsyms_for_kcore(struct dso *dso, struct map *map,
 		curr_map = map_groups__find(kmaps, map->type, pos->start);
 
 		if (!curr_map || (filter && filter(curr_map, pos))) {
-			rb_erase(&pos->rb_node, root);
+			rb_erase_init(&pos->rb_node, root);
 			symbol__delete(pos);
 		} else {
 			pos->start -= curr_map->start - curr_map->pgoff;
 			if (pos->end)
 				pos->end -= curr_map->start - curr_map->pgoff;
 			if (curr_map != map) {
-				rb_erase(&pos->rb_node, root);
+				rb_erase_init(&pos->rb_node, root);
 				symbols__insert(
 					&curr_map->dso->symbols[curr_map->type],
 					pos);

@@ -1173,7 +1173,7 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
 	/* Add new maps */
 	while (!list_empty(&md.maps)) {
 		new_map = list_entry(md.maps.next, struct map, node);
-		list_del(&new_map->node);
+		list_del_init(&new_map->node);
 		if (new_map == replacement_map) {
 			map->start	= new_map->start;
 			map->end	= new_map->end;

@@ -1211,7 +1211,7 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
 out_err:
 	while (!list_empty(&md.maps)) {
 		map = list_entry(md.maps.next, struct map, node);
-		list_del(&map->node);
+		list_del_init(&map->node);
 		map__delete(map);
 	}
 	close(fd);