[PATCH 3/6] perf inject: Enter namespace when reading build-id

From: Namhyung Kim
Date: Mon Sep 28 2020 - 03:53:21 EST


It should be in a proper mnt namespace when accessing the file.

I think this had no problem since the build-id was actually read from
map__load() -> dso__load() already. But I'd like to change it in the
following commit.

Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/builtin-inject.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index 2c5e23d73a8a..670157db2502 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -23,6 +23,7 @@
#include "util/symbol.h"
#include "util/synthetic-events.h"
#include "util/thread.h"
+#include "util/namespaces.h"
#include <linux/err.h>

#include <subcmd/parse-options.h>
@@ -419,16 +420,19 @@ static int perf_event__repipe_tracing_data(struct perf_session *session,

static int dso__read_build_id(struct dso *dso)
{
+ struct nscookie nsc;
+
if (dso->has_build_id)
return 0;

+ nsinfo__mountns_enter(dso->nsinfo, &nsc);
if (filename__read_build_id(dso->long_name, dso->build_id,
sizeof(dso->build_id)) > 0) {
dso->has_build_id = true;
- return 0;
}
+ nsinfo__mountns_exit(&nsc);

- return -1;
+ return dso->has_build_id ? 0 : -1;
}

static int dso__inject_build_id(struct dso *dso, struct perf_tool *tool,
--
2.28.0.681.g6f77f65b4e-goog