diff -ru Python-3.5.1/Modules/signalmodule.c Python-3.5.1-fixed//Modules/signalmodule.c
--- Python-3.5.1/Modules/signalmodule.c	2015-12-07 02:39:10.000000000 +0100
+++ Python-3.5.1-fixed//Modules/signalmodule.c	2017-04-12 18:51:34.506672570 +0200
@@ -441,12 +441,13 @@
     }
     else
         func = signal_handler;
+    /* Check for pending signals before changing signal handler */
+    if (PyErr_CheckSignals()) return NULL;
     if (PyOS_setsig(signalnum, func) == SIG_ERR) {
         PyErr_SetFromErrno(PyExc_OSError);
         return NULL;
     }
     old_handler = Handlers[signalnum].func;
-    Handlers[signalnum].tripped = 0;
     Py_INCREF(handler);
     Handlers[signalnum].func = handler;
     if (old_handler != NULL)
Only in Python-3.5.1-fixed//Modules: signalmodule.c.orig
Only in Python-3.5.1-fixed//Modules: signalmodule.c.rej
Only in Python-3.5.1/Modules: .signalmodule.c.swp