[PATCH 5.19 149/207] perf tools: Honor namespace when synthesizing build-ids

Greg Kroah-Hartman
2022-09-26T12:24:02Z

From: Namhyung Kim <namhyung@kernel.org>

[ Upstream commit 999e4eaa4b3691acf85d094836260ec4b66c74fd ]

It needs to enter the namespace before reading a file.

Fixes: 4183a8d70a288627 ("perf tools: Allow synthesizing the build id for kernel/modules/tasks in PERF_RECORD_MMAP2")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20220920222822.2171056-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/util/synthetic-events.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
index 84d17bd4efae..64e273b2b1b2 100644
--- a/tools/perf/util/synthetic-events.c
+++ b/tools/perf/util/synthetic-events.c
@@ -367,13 +367,24 @@ static void perf_record_mmap2__read_build_id(struct perf_record_mmap2 *event,
bool is_kernel)
{
struct build_id bid;
+ struct nsinfo *nsi;
+ struct nscookie nc;
int rc;

- if (is_kernel)
+ if (is_kernel) {
rc = sysfs__read_build_id("/sys/kernel/notes", &bid);
- else
- rc = filename__read_build_id(event->filename, &bid) > 0 ? 0 : -1;
+ goto out;
+ }
+
+ nsi = nsinfo__new(event->pid);
+ nsinfo__mountns_enter(nsi, &nc);

+ rc = filename__read_build_id(event->filename, &bid) > 0 ? 0 : -1;
+
+ nsinfo__mountns_exit(&nc);
+ nsinfo__put(nsi);
+
+out:
if (rc == 0) {
memcpy(event->build_id, bid.data, sizeof(bid.data));
event->build_id_size = (u8) bid.size;
--
2.35.1