diff --git a/src/libsysprof/sysprof-proxy-source.c b/src/libsysprof/sysprof-proxy-source.c
index afb1a582..186b3dbf 100644
--- a/src/libsysprof/sysprof-proxy-source.c
+++ b/src/libsysprof/sysprof-proxy-source.c
@@ -476,7 +476,8 @@ sysprof_proxy_source_stop (SysprofSource *source)
                                   -1,
                                   NULL,
                                   sysprof_proxy_source_stop_cb,
-                                  g_steal_pointer (&monitor));
+                                  monitor);
+          monitor = NULL; /* stolen */
         }
       else
         {