Commit 99deaf55 authored Feb 28, 2025 by Arnaldo Carvalho de Melo Committed by Namhyung Kim Mar 05, 2025

perf maps: Introduce map__set_kmap_maps() for kernel maps



We need to set it in other places than __maps__insert(), so that we can
have access to the 'struct maps' from a kernel 'struct map'.

When building perf with 'DEBUG=1' we can notice it failing a consistency
check done in the check_invariants() function:

  root@number:~# perf record -- perf test -w offcpu
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.040 MB perf.data (23 samples) ]
  perf: util/maps.c:95: check_invariants: Assertion `map__end(prev) <= map__end(map)' failed.
  Aborted (core dumped)
  root@number:~#

The investigation on that was happening bisected to 876e80cf
("perf tools: Fixup end address of modules"), and the following patches
will plug the problems found, this patch is just legwork on that
direction.

Use the map__set_kmap_maps() name as per a review comment from Ian
Rogers, later there are further suggestions from him on getting rid of
the kmaps variable, see the thread referenced in the Link below.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/lkml/Z74V0hZXrTLM6VIJ@x1
Link: https://lore.kernel.org/r/20250228211734.33781-2-acme@kernel.org


Signed-off-by: Namhyung Kim <namhyung@kernel.org>

parent 74fb903b

tools/perf/util/maps.c

+21 −8

Original line number	Diff line number	Diff line
		@@ -428,11 +428,29 @@ static unsigned int maps__by_name_index(const struct maps *maps, const struct ma
		return -1;
		}

		static void map__set_kmap_maps(struct map map, struct maps maps)
		{
		struct dso *dso;

		if (map == NULL)
		return;

		dso = map__dso(map);

		if (dso && dso__kernel(dso)) {
		struct kmap *kmap = map__kmap(map);

		if (kmap)
		kmap->kmaps = maps;
		else
		pr_err("Internal error: kernel dso with non kernel map\n");
		}
		}

		static int __maps__insert(struct maps maps, struct map new)
		{
		struct map **maps_by_address = maps__maps_by_address(maps);
		struct map **maps_by_name = maps__maps_by_name(maps);
		const struct dso *dso = map__dso(new);
		unsigned int nr_maps = maps__nr_maps(maps);
		unsigned int nr_allocate = RC_CHK_ACCESS(maps)->nr_maps_allocated;

		@@ -483,14 +501,9 @@ static int __maps__insert(struct maps maps, struct map new)
		}
		if (map__end(new) < map__start(new))
		RC_CHK_ACCESS(maps)->ends_broken = true;
		if (dso && dso__kernel(dso)) {
		struct kmap *kmap = map__kmap(new);

		if (kmap)
		kmap->kmaps = maps;
		else
		pr_err("Internal error: kernel dso with non kernel map\n");
		}
		map__set_kmap_maps(new, maps);

		return 0;
		}