Commit 0d11fab3 authored by Namhyung Kim's avatar Namhyung Kim
Browse files

perf maps: Fixup maps_by_name when modifying maps_by_address 



We can't just replacing the map in the maps_by_address and not touching
on the maps_by_name, that would leave the refcount as 1 and thus trip
another consistency check, this one:

  perf: util/maps.c:110: check_invariants:
  	Assertion `refcount_read(map__refcnt(map)) > 1' failed.

  106         /*
  107          * Maps by name maps should be in maps_by_address, so
  108          * the reference count should be higher.
  109          */
  110         assert(refcount_read(map__refcnt(map)) > 1);

Committer notice:

Initialize the newly added 'ni' variable, that really can't be
accessed unitialized trips some gcc versions, like:

  12    20.00 archlinux:base                : FAIL gcc version 13.2.1 20230801 (GCC)
    util/maps.c: In function ‘__maps__fixup_overlap_and_insert’:
    util/maps.c:896:54: error: ‘ni’ may be used uninitialized [-Werror=maybe-uninitialized]
      896 |                                 map__put(maps_by_name[ni]);
          |                                                      ^
    util/maps.c:816:25: note: ‘ni’ was declared here
      816 |         unsigned int i, ni;
          |                         ^~
    cc1: all warnings being treated as errors
    make[3]: *** [/git/perf-6.14.0-rc1/tools/build/Makefile.build:138: util] Error 2

Reported-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: default avatarIan Rogers <irogers@google.com>
Link: https://lore.kernel.org/lkml/Z79std66tPq-nqsD@google.com
Link: https://lore.kernel.org/r/20250228211734.33781-5-acme@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
parent f7a46e02

tools/perf/util/maps.c

+23 −1
Original line number Diff line number Diff line
@@ -813,7 +813,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new) 
{

	int err = 0;

	FILE *fp = debug_file();

	unsigned int i;

	unsigned int i, ni = INT_MAX; // Some gcc complain, but depends on maps_by_name...



	if (!maps__maps_by_address_sorted(maps))

		__maps__sort_by_address(maps);
@@ -824,6 +824,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new) 
	 */

	for (i = first_ending_after(maps, new); i < maps__nr_maps(maps); ) {

		struct map **maps_by_address = maps__maps_by_address(maps);

		struct map **maps_by_name = maps__maps_by_name(maps);

		struct map *pos = maps_by_address[i];

		struct map *before = NULL, *after = NULL;
@@ -843,6 +844,9 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new) 
			map__fprintf(pos, fp);

		}



		if (maps_by_name)

			ni = maps__by_name_index(maps, pos);



		/*

		 * Now check if we need to create new maps for areas not

		 * overlapped by the new map:
@@ -887,6 +891,12 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new) 
		if (before) {

			map__put(maps_by_address[i]);

			maps_by_address[i] = before;



			if (maps_by_name) {

				map__put(maps_by_name[ni]);

				maps_by_name[ni] = map__get(before);

			}



			/* Maps are still ordered, go to next one. */

			i++;

			if (after) {
@@ -908,6 +918,12 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new) 
			 */

			map__put(maps_by_address[i]);

			maps_by_address[i] = map__get(new);



			if (maps_by_name) {

				map__put(maps_by_name[ni]);

				maps_by_name[ni] = map__get(new);

			}



			err = __maps__insert_sorted(maps, i + 1, after, NULL);

			map__put(after);

			check_invariants(maps);
@@ -926,6 +942,12 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new) 
				 */

				map__put(maps_by_address[i]);

				maps_by_address[i] = map__get(new);



				if (maps_by_name) {

					map__put(maps_by_name[ni]);

					maps_by_name[ni] = map__get(new);

				}



				check_invariants(maps);

				return err;

			}