linux-kernel - [PATCH 16/20] perf trace: free syscall->arg

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Message-Id: <d68f25c043d30464ac9fa79c3399e18f429bca82.1626343282.git.rickyman7@gmail.com>
Date:   Thu, 15 Jul 2021 18:07:21 +0200
From:   Riccardo Mancini <rickyman7@...il.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Ian Rogers <irogers@...gle.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Jiri Olsa <jolsa@...hat.com>, linux-kernel@...r.kernel.org,
        linux-perf-users@...r.kernel.org,
        Riccardo Mancini <rickyman7@...il.com>
Subject: [PATCH 16/20] perf trace: free syscall->arg_fmt

ASan reports several memory leaks running the perf test
"88: Check open filename arg using perf trace + vfs_getname".
The second of these leaks is caused by the arg_fmt field of syscall not
being deallocated.

This patch adds a new function syscall__exit which is called on all
syscalls.table entries in trace__exit, which will free the arg_fmt
field.

Signed-off-by: Riccardo Mancini <rickyman7@...il.com>
---
 tools/perf/builtin-trace.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index fe26d87ca8ccc14d..d67f02d237eb0c7e 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2266,6 +2266,14 @@ static void *syscall__augmented_args(struct syscall *sc, struct perf_sample *sam
 	return augmented_args;
 }
 
+static void syscall__exit(struct syscall *sc)
+{
+	if (!sc)
+		return;
+
+	free(sc->arg_fmt);
+}
+
 static int trace__sys_enter(struct trace *trace, struct evsel *evsel,
 			    union perf_event *event __maybe_unused,
 			    struct perf_sample *sample)
@@ -4703,9 +4711,15 @@ static int trace__config(const char *var, const char *value, void *arg)
 
 static void trace__exit(struct trace *trace)
 {
+	int i;
+
 	strlist__delete(trace->ev_qualifier);
 	free(trace->ev_qualifier_ids.entries);
-	free(trace->syscalls.table);
+	if (trace->syscalls.table) {
+		for (i = 0; i <= trace->sctbl->syscalls.max_id; i++)
+			syscall__exit(&trace->syscalls.table[i]);
+		free(trace->syscalls.table);
+	}
 	syscalltbl__delete(trace->sctbl);
 	zfree(&trace->perfconfig_events);
 }
-- 
2.31.1