diff --git a/src/journal-remote/journal-remote.c b/src/journal-remote/journal-remote.c
index 0539d4d0bf..9fd6a23076 100644
--- a/src/journal-remote/journal-remote.c
+++ b/src/journal-remote/journal-remote.c
@@ -429,9 +429,14 @@ static int dispatch_raw_source_until_block(sd_event_source *event,
         sd_event_source_ref(event);
 
         r = journal_remote_handle_raw_source(event, source->importer.fd, EPOLLIN, journal_remote_server_global);
-        if (r != 1)
+        if (r != 1) {
+                int k;
+
                 /* No more data for now */
-                sd_event_source_set_enabled(event, SD_EVENT_OFF);
+                k = sd_event_source_set_enabled(event, SD_EVENT_OFF);
+                if (k < 0)
+                        r = k;
+        }
 
         sd_event_source_unref(event);
 
@@ -449,10 +454,15 @@ static int dispatch_raw_source_event(sd_event_source *event,
         assert(source->buffer_event);
 
         r = journal_remote_handle_raw_source(event, fd, EPOLLIN, journal_remote_server_global);
-        if (r == 1)
+        if (r == 1) {
+                int k;
+
                 /* Might have more data. We need to rerun the handler
                  * until we are sure the buffer is exhausted. */
-                sd_event_source_set_enabled(source->buffer_event, SD_EVENT_ON);
+                k = sd_event_source_set_enabled(source->buffer_event, SD_EVENT_ON);
+                if (k < 0)
+                        r = k;
+        }
 
         return r;
 }
diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c
index 37efe3f425..f9e2be155e 100644
--- a/src/libsystemd/sd-event/sd-event.c
+++ b/src/libsystemd/sd-event/sd-event.c
@@ -2959,7 +2959,7 @@ static int event_source_leave_ratelimit(sd_event_source *s, bool run_callback) {
                 if (s->n_ref == 0)
                         source_free(s);
                 else if (r < 0)
-                        sd_event_source_set_enabled(s, SD_EVENT_OFF);
+                        assert_se(sd_event_source_set_enabled(s, SD_EVENT_OFF) >= 0);
 
                 return 1;
         }
diff --git a/src/test/test-strxcpyx.c b/src/test/test-strxcpyx.c
index 4b6d8ebce3..c68fe3c064 100644
--- a/src/test/test-strxcpyx.c
+++ b/src/test/test-strxcpyx.c
@@ -83,10 +83,13 @@ static void test_sd_event_code_migration(void) {
         char c[100 * DECIMAL_STR_MAX(unsigned) + 1], *p;
         unsigned i;
         size_t l;
-        int o;
+        int o, r;
 
-        for (i = o = 0; i < 100; i++)
-                o += snprintf(&b[o], sizeof(b) - o, "%u ", i);
+        for (i = o = 0; i < 100; i++) {
+                r = snprintf(&b[o], sizeof(b) - o, "%u ", i);
+                assert_se(r >= 0 && r < (int) sizeof(b) - o);
+                o += r;
+        }
 
         p = c;
         l = sizeof(c);