diff -r 3f739f42be51 Modules/signalmodule.c
--- a/Modules/signalmodule.c	Mon Oct 01 07:18:55 2012 +0300
+++ b/Modules/signalmodule.c	Tue Oct 02 22:46:11 2012 -0300
@@ -174,6 +174,11 @@
 static int
 checksignals_witharg(void * unused)
 {
+    int error = (int) unused;
+    if (error == EBADF) {
+        PyErr_Format(PyExc_ValueError, "Invalid wakeup FD");
+        return NULL;
+    }
     return PyErr_CheckSignals();
 }
 
@@ -185,7 +190,10 @@
     Handlers[sig_num].tripped = 1;
     if (wakeup_fd != -1) {
         byte = (unsigned char)sig_num;
-        write(wakeup_fd, &byte, 1);
+        if (write(wakeup_fd, &byte, 1) == -1) {
+            Py_AddPendingCall(checksignals_witharg, errno);
+            return;
+        }
     }
     if (is_tripped)
         return;