perf maps: Ensure kmap is set up for all inserts

__maps__fixup_overlap_and_insert may split or directly insert a map,
when doing this the map may need to have a kmap set up for the sake of
the kmaps. The missing kmap set up fails the check_invariants test in
maps, later "Internal error" reports from map__kmap and ultimately
causes segfaults.

Similar fixes were added in commit e0e4e0b8b7 ("perf maps: Add
missing map__set_kmap_maps() when replacing a kernel map") and commit
25d9c0301d ("perf maps: Set the kmaps for newly created/added kernel
maps") but they missed cases. To try to reduce the risk of this,
update the kmap directly following any manual insert. This identified
another problem in maps__copy_from.

Fixes: e0e4e0b8b7 ("perf maps: Add missing map__set_kmap_maps() when replacing a kernel map")
Fixes: 25d9c0301d ("perf maps: Set the kmaps for newly created/added kernel maps")
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
This commit is contained in:
Ian Rogers
2025-09-14 11:18:08 -07:00
committed by Namhyung Kim
parent 7947ad1561
commit 20c9ccffcc

View File

@@ -477,6 +477,7 @@ static int __maps__insert(struct maps *maps, struct map *new)
}
/* Insert the value at the end. */
maps_by_address[nr_maps] = map__get(new);
map__set_kmap_maps(new, maps);
if (maps_by_name)
maps_by_name[nr_maps] = map__get(new);
@@ -502,8 +503,6 @@ static int __maps__insert(struct maps *maps, struct map *new)
if (map__end(new) < map__start(new))
RC_CHK_ACCESS(maps)->ends_broken = true;
map__set_kmap_maps(new, maps);
return 0;
}
@@ -891,6 +890,7 @@ 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;
map__set_kmap_maps(before, maps);
if (maps_by_name) {
map__put(maps_by_name[ni]);
@@ -918,6 +918,7 @@ 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);
map__set_kmap_maps(new, maps);
if (maps_by_name) {
map__put(maps_by_name[ni]);
@@ -942,14 +943,13 @@ 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);
map__set_kmap_maps(new, maps);
if (maps_by_name) {
map__put(maps_by_name[ni]);
maps_by_name[ni] = map__get(new);
}
map__set_kmap_maps(new, maps);
check_invariants(maps);
return err;
}
@@ -1019,6 +1019,7 @@ int maps__copy_from(struct maps *dest, struct maps *parent)
err = unwind__prepare_access(dest, new, NULL);
if (!err) {
dest_maps_by_address[i] = new;
map__set_kmap_maps(new, dest);
if (dest_maps_by_name)
dest_maps_by_name[i] = map__get(new);
RC_CHK_ACCESS(dest)->nr_maps = i + 1;