[PATCH 6/6] perf machine: Fix insertion of PERF_RECORD_KSYMBOL related kernel maps

Arnaldo Carvalho de Melo
2025-02-28T21:18:05Z

From: Namhyung Kim <namhyung@kernel.org>

This was detected at the end of a 'perf record' session when build-id
collection was enabled and thus the BPF programs put in place while the
session was running, some even put in place by perf itself were
processed and inserted, with some overlaps related to BPF trampolines
and programs took place.

Using maps__fixup_overlap_and_insert() instead of maps__insert() "fixes"
the problem, in the sense that overlaps will be dealt with and then the
consistency will be kept, but it would be interesting to fully
understand why such overlaps take place and how to deal with them when
doing symbol resolution.

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Suggested-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.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/CAP-5=fXEEMFgPF2aZhKsfrY_En+qoqX20dWfuE_ad73Uxf0ZHQ@mail.gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/machine.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index f7df01adad61ceea..a81ffd2d1a054d60 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -718,7 +718,7 @@ static int machine__process_ksymbol_register(struct machine *machine,

map__set_start(map, event->ksymbol.addr);
map__set_end(map, map__start(map) + event->ksymbol.len);
- err = maps__insert(machine__kernel_maps(machine), map);
+ err = maps__fixup_overlap_and_insert(machine__kernel_maps(machine), map);
if (err) {
err = -ENOMEM;
goto out;
--
2.48.1