Re: [PATCH] vl: fix leak of qdict_crumple return value

[Markus Armbruster <armbru@redhat.com>]

Paolo Bonzini <pbonzini@redhat.com> writes:

> Coverity reports that qemu_parse_config_group is returning without
> unrefing the "crumpled" dictionary in case its top level item is a
> list.  But actually the contract with qemu_record_config_group is
> the same as for qemu_parse_config_group itself: if those function
> need to stash the dictionary they get, they have to take a reference
> themselves (currently this is never the case for either function).
> Therefore, just add an unconditional qobject_unref(crumpled) to
> qemu_parse_config_group.
>
> Reported-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Do we want

  Fixes: c0d4aa82f895af67cbf7772324e05605e22b4162

here?

> ---
>  softmmu/vl.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/softmmu/vl.c b/softmmu/vl.c
> index 2004d57108..7b54ddf6f4 100644
> --- a/softmmu/vl.c
> +++ b/softmmu/vl.c
> @@ -2196,9 +2196,10 @@ static void qemu_parse_config_group(const char *group, QDict *qdict,
>      if (qobject_type(crumpled) != QTYPE_QDICT) {
>          assert(qobject_type(crumpled) == QTYPE_QLIST);
>          error_setg(errp, "Lists cannot be at top level of a configuration section");
> -        return;
> +    } else {
> +        qemu_record_config_group(group, qobject_to(QDict, crumpled), false, errp);
>      }
> -    qemu_record_config_group(group, qobject_to(QDict, crumpled), false, errp);
> +    qobject_unref(crumpled);
>  }
>  
>  static void qemu_read_default_config_file(Error **errp)

Minimally invasive fix, but the result is a bit awkward.  Possibly
neater:

       if (qobject_type(crumpled) == QTYPE_QLIST) {
           error_setg(errp,
                      "Lists cannot be at top level of a configuration section");
       } else {
           assert(qobject_type(crumpled) == QTYPE_QDICT);
           qemu_record_config_group(group, qobject_to(QDict, crumpled),
                                    false, errp);
       }
       qobject_unref(crumpled);

Regardless:
Reviewed-by: Markus Armbruster <armbru@redhat.com>