perf scripting: Avoid leaking the scripting_context variable

commit cf346d5b upstream.

Both register_perl_scripting() and register_python_scripting() allocate
this variable, fix it by checking if it already was.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 7e4b21b8 ("perf/scripts: Add Python scripting engine")
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/perf/util/trace-event-scripting.c

@@ -95,7 +95,8 @@ static void register_python_scripting(struct scripting_ops *scripting_ops)
 	if (err)
 		die("error registering py script extension");
 
-	scripting_context = malloc(sizeof(struct scripting_context));
+	if (scripting_context == NULL)
+		scripting_context = malloc(sizeof(*scripting_context));
 }
 
 #ifdef NO_LIBPYTHON
@@ -159,7 +160,8 @@ static void register_perl_scripting(struct scripting_ops *scripting_ops)
 	if (err)
 		die("error registering pl script extension");
 
-	scripting_context = malloc(sizeof(struct scripting_context));
+	if (scripting_context == NULL)
+		scripting_context = malloc(sizeof(*scripting_context));
 }
 
 #ifdef NO_LIBPERL