[PATCH 1/6] perf maps: Introduce map__set_kmap_maps() for kernel maps

Arnaldo Carvalho de Melo
2025-02-28T21:17:45Z

From: Arnaldo Carvalho de Melo <acme@redhat.com>

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 876e80cf83d10585
("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.

Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/lkml/Z74V0hZXrTLM6VIJ@x1
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/maps.c | 29 +++++++++++++++++++++--------
1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c
index 09c9cc326c08d435..51b507233269d8b4 100644
--- a/tools/perf/util/maps.c
+++ b/tools/perf/util/maps.c
@@ -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;
}

--
2.48.1