Re: [Qemu-devel] [PATCH] Fix some memory leaks in test-visitor-serialization

[mdroth <mdroth@linux.vnet.ibm.com>]

On Tue, Mar 26, 2013 at 05:46:55PM -0400, Stefan Berger wrote:
> This patch fixes some of the memory leaks in
> test-visitor-serialization but not all of them.
> 
> Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
> 
> ---
>  tests/test-visitor-serialization.c |   17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> Index: qemu-git.pt/tests/test-visitor-serialization.c
> ===================================================================
> --- qemu-git.pt.orig/tests/test-visitor-serialization.c
> +++ qemu-git.pt/tests/test-visitor-serialization.c
> @@ -258,6 +258,7 @@ static void test_primitives(gconstpointe
>      g_assert(pt_copy != NULL);
>      if (pt->type == PTYPE_STRING) {
>          g_assert_cmpstr(pt->value.string, ==, pt_copy->value.string);
> +        g_free((char *)pt_copy->value.string);
>      } else if (pt->type == PTYPE_NUMBER) {
>          /* we serialize with %f for our reference visitors, so
> rather than fuzzy
>           * floating math to test "equality", just compare the
> formatted values
> @@ -275,6 +276,7 @@ static void test_primitives(gconstpointe
> 
>      ops->cleanup(serialize_data);
>      g_free(args);
> +    g_free(pt_copy);
>  }
> 
>  static void test_struct(gconstpointer opaque)
> @@ -637,6 +639,7 @@ PrimitiveType pt_values[] = {
>  /* visitor-specific op implementations */
> 
>  typedef struct QmpSerializeData {
> +    QObject *obj;
>      QmpOutputVisitor *qov;
>      QmpInputVisitor *qiv;
>  } QmpSerializeData;
> @@ -656,10 +659,10 @@ static void qmp_deserialize(void **nativ
>  {
>      QmpSerializeData *d = datap;
>      QString *output_json =
> qobject_to_json(qmp_output_get_qobject(d->qov));
> -    QObject *obj = qobject_from_json(qstring_get_str(output_json));
> 
> +    d->obj = qobject_from_json(qstring_get_str(output_json));
>      QDECREF(output_json);
> -    d->qiv = qmp_input_visitor_new(obj);
> +    d->qiv = qmp_input_visitor_new(d->obj);
>      visit(qmp_input_get_visitor(d->qiv), native_out, errp);
>  }
> 
> @@ -668,9 +671,13 @@ static void qmp_cleanup(void *datap)
>      QmpSerializeData *d = datap;
>      qmp_output_visitor_cleanup(d->qov);
>      qmp_input_visitor_cleanup(d->qiv);
> +    qobject_decref(d->obj);

We can actually call this just after passing the qobject to
qmp_input_visitor_new(), which will lead to it getting cleaned up
in qmp_input_visitor_cleanup(). That way we wouldn't need to hold
on to the reference in d->obj.

But this works too, and looks like string visitor still requires
we hang on to the reference to free it, so either way:

Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>

> +
> +    g_free(d);
>  }
> 
>  typedef struct StringSerializeData {
> +    char *string;
>      StringOutputVisitor *sov;
>      StringInputVisitor *siv;
>  } StringSerializeData;
> @@ -690,15 +697,19 @@ static void string_deserialize(void **na
>  {
>      StringSerializeData *d = datap;
> 
> -    d->siv = string_input_visitor_new(string_output_get_string(d->sov));
> +    d->string = string_output_get_string(d->sov);
> +    d->siv = string_input_visitor_new(d->string);
>      visit(string_input_get_visitor(d->siv), native_out, errp);
>  }
> 
>  static void string_cleanup(void *datap)
>  {
>      StringSerializeData *d = datap;
> +
>      string_output_visitor_cleanup(d->sov);
>      string_input_visitor_cleanup(d->siv);
> +    g_free(d->string);
> +    g_free(d);
>  }
> 
>  /* visitor registration, test harness */
>