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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Namhyung Kim <namhyung@kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Ian Rogers <irogers@google.com>, Jiri Olsa <jolsa@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 109/148] perf tools: Honor namespace when synthesizing build-ids
Date:   Mon, 26 Sep 2022 12:12:23 +0200
Message-Id: <20220926100800.204911338@linuxfoundation.org>
In-Reply-To: <20220926100756.074519146@linuxfoundation.org>
References: <20220926100756.074519146@linuxfoundation.org>
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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 a7e981b2d7de..c69ad7a1a6a7 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