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From:   Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
To:     Arnaldo Carvalho de Melo <acme@kernel.org>
Cc:     Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Alexander Antonov <alexander.antonov@linux.intel.com>,
        Alexei Budankov <abudankov@huawei.com>
Subject: [PATCH] perf data: Fix double free in perf_session__delete
Date:   Fri, 18 Feb 2022 14:30:08 +0300
Message-Id: <20220218113008.24416-1-alexey.v.bayduraev@linux.intel.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

When perf_data__create_dir fails, it calls close_dir, but
perf_session__delete also calls close_dir and since dir.version and
dir.nr was initialized by perf_data__create_dir, a double free occurs.
This patch moves the initialization of dir.version and dir.nr after
successful initialization of dir.files, that prevents double freeing.
This behavior is already implemented in perf_data__open_dir. The patch
also adds a missing error message in case data directory creation fails.

Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
---
 tools/perf/builtin-record.c | 4 +++-
 tools/perf/util/data.c      | 7 +++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 0bc6529814b2..0306d5911de2 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1186,8 +1186,10 @@ static int record__mmap_evlist(struct record *rec,
 
 	if (record__threads_enabled(rec)) {
 		ret = perf_data__create_dir(&rec->data, evlist->core.nr_mmaps);
-		if (ret)
+		if (ret) {
+			pr_err("Failed to create data directory: %s\n", strerror(errno));
 			return ret;
+		}
 		for (i = 0; i < evlist->core.nr_mmaps; i++) {
 			if (evlist->mmap)
 				evlist->mmap[i].file = &rec->data.dir.files[i];
diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
index f5d260b1df4d..15a4547d608e 100644
--- a/tools/perf/util/data.c
+++ b/tools/perf/util/data.c
@@ -44,10 +44,6 @@ int perf_data__create_dir(struct perf_data *data, int nr)
 	if (!files)
 		return -ENOMEM;
 
-	data->dir.version = PERF_DIR_VERSION;
-	data->dir.files   = files;
-	data->dir.nr      = nr;
-
 	for (i = 0; i < nr; i++) {
 		struct perf_data_file *file = &files[i];
 
@@ -62,6 +58,9 @@ int perf_data__create_dir(struct perf_data *data, int nr)
 		file->fd = ret;
 	}
 
+	data->dir.version = PERF_DIR_VERSION;
+	data->dir.files   = files;
+	data->dir.nr      = nr;
 	return 0;
 
 out_err:
-- 
2.19.0