From: Simon Marchi <simon.marchi@efficios.com>
Date: Thu, 18 Apr 2019 18:00:29 +0000 (-0400)
Subject: Fix: cli: Acquire reference on bt_value_null while parsing args
X-Git-Tag: v2.0.0-pre5~83
X-Git-Url: http://git.efficios.com/?p=babeltrace.git;a=commitdiff_plain;h=130417948312e8aa9ab10b077953d40c9a56101b

Fix: cli: Acquire reference on bt_value_null while parsing args

In bt_config_query_from_args, we initialize "params" to point to
bt_value_null without acquiring a reference:

    bt_value *params = bt_value_null;

When handling OPT_PARAMS, lower, we call "put" on it before assigning
params to something else:

    bt_value_put_ref(params);

This causes bt_value_null's refcount to drop to 0 and its release to be
called (which should never happen, since its refcount is initialized to
1).  This warning is shown:

    $ ./cli/babeltrace query
    ...
    04-18 13:56:12.267 10081 10081 W VALUES bt_value_null_instance_release_func@value.c:73 Releasing the null value singleton: addr=0x7f882eaf1b60

Fix it by acquiring a new reference in the beginning.

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
---

diff --git a/cli/babeltrace-cfg-cli-args.c b/cli/babeltrace-cfg-cli-args.c
index f501ebcd..920d2a3f 100644
--- a/cli/babeltrace-cfg-cli-args.c
+++ b/cli/babeltrace-cfg-cli-args.c
@@ -1993,7 +1993,10 @@ struct bt_config *bt_config_query_from_args(int argc, const char *argv[],
 	int ret;
 	struct bt_config *cfg = NULL;
 	const char *leftover;
-	bt_value *params = bt_value_null;
+	bt_value *params;
+
+	params = bt_value_null;
+	bt_value_get_ref(bt_value_null);
 
 	*retcode = 0;
 	cfg = bt_config_query_create(initial_plugin_paths);