s390x/cpumodel: Fix query-cpu-definitions error API violations

qmp_query_cpu_definitions() passes @errp to get_max_cpu_model(), then
frees any error it gets back.  This effectively ignores errors.
Dereferencing @errp is wrong; see the big comment in error.h.  Passing
@errp is also wrong, because it works only as long as @errp is neither
@error_fatal nor @error_abort.  Introduced in commit 38cba1f4d8
"s390x: return unavailable features via query-cpu-definitions".

No caller actually passes such @errp values.

Fix anyway: simply pass NULL to get_max_cpu_model().

Cc: David Hildenbrand <david@redhat.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-Id: <20191204093625.14836-16-armbru@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
index 3ed301b5e50971a7492232c6621e351c10d4e461..547bab8ac3923dfb6a10774fdcd3e42723cf4112 100644 (file)
--- a/target/s390x/cpu_models.c
+++ b/target/s390x/cpu_models.c
@@ -462,11 +462,7 @@ CpuDefinitionInfoList *qmp_query_cpu_definitions(Error **errp)
         .list = NULL,
     };
 
-    list_data.model = get_max_cpu_model(errp);
-    if (*errp) {
-        error_free(*errp);
-        *errp = NULL;
-    }
+    list_data.model = get_max_cpu_model(NULL);
 
     object_class_foreach(create_cpu_model_list, TYPE_S390_CPU, false,
                          &list_data);