perf probe: Fix memory leak when synthesizing SDT probes

The argv_split() function must be paired with argv_free(), else we must
keep a reference to the argv array received or do the freeing ourselves,
in synthesize_sdt_probe_command() we were simply leaking that argv[]
array.

Fixes: 3b1f831 ("perf probe: Add sdt probes arguments into the uprobe cmd string")
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Truong <alexandre.truong@arm.com>
Cc: Alexis Berlemont <alexis.berlemont@gmail.com>
Cc: He Zhe <zhe.he@windriver.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201224135139.GF477817@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/probe-file.c

@@ -791,7 +791,7 @@ static char *synthesize_sdt_probe_command(struct sdt_note *note,
 					const char *sdtgrp)
 {
 	struct strbuf buf;
-	char *ret = NULL, **args;
+	char *ret = NULL;
 	int i, args_count, err;
 	unsigned long long ref_ctr_offset;
 
@@ -813,12 +813,19 @@ static char *synthesize_sdt_probe_command(struct sdt_note *note,
 		goto out;
 
 	if (note->args) {
-		args = argv_split(note->args, &args_count);
+		char **args = argv_split(note->args, &args_count);
+
+		if (args == NULL)
+			goto error;
 
 		for (i = 0; i < args_count; ++i) {
-			if (synthesize_sdt_probe_arg(&buf, i, args[i]) < 0)
+			if (synthesize_sdt_probe_arg(&buf, i, args[i]) < 0) {
+				argv_free(args);
 				goto error;
+			}
 		}
+
+		argv_free(args);
 	}
 
 out: