diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c
index 1224654290c71..f4ede985de797 100644
--- a/src/libsystemd/sd-event/sd-event.c
+++ b/src/libsystemd/sd-event/sd-event.c
@@ -1203,11 +1203,12 @@ static sd_event_source *source_new(sd_event *e, bool floating, EventSourceType t
         assert(type < _SOURCE_EVENT_SOURCE_TYPE_MAX);
         assert(size_table[type] > 0);
 
-        /* We use expand_to_usable() here to tell gcc that it should consider this an object of the full
-         * size, even if we only allocate the initial part we need. */
-        s = expand_to_usable(malloc0(size_table[type]), sizeof(sd_event_source));
+        s = malloc0(size_table[type]);
         if (!s)
                 return NULL;
+        /* We use expand_to_usable() here to tell gcc that it should consider this an object of the full
+         * size, even if we only allocate the initial part we need. */
+        s = expand_to_usable(s, sizeof(sd_event_source));
 
         /* Note: we cannot use compound initialization here, because sizeof(sd_event_source) is likely larger
          * than what we allocated here. */