diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index b3f5904..9041848 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -1784,7 +1784,7 @@
 int
 _PyOS_InterruptOccurred(PyThreadState *tstate)
 {
-    assert(tstate != NULL);
+    _Py_EnsureTstateNotNULL(tstate);
     if (!_Py_ThreadCanHandleSignals(tstate->interp)) {
         return 0;
     }