diff -r bd5c74def80d Lib/test/test_signal.py
--- a/Lib/test/test_signal.py	Thu Oct 04 02:43:02 2012 +0200
+++ b/Lib/test/test_signal.py	Wed Oct 03 22:56:21 2012 -0300
@@ -9,7 +9,9 @@
 import subprocess
 import traceback
 import sys, os, time, errno
-from test.script_helper import assert_python_ok, spawn_python
+from test.script_helper import assert_python_ok, \
+                               assert_python_failure, \
+                               spawn_python
 try:
     import threading
 except ImportError:
@@ -265,6 +267,43 @@
 
         assert_python_ok('-c', code)
 
+    def test_wakeup_read_only_fd(self):
+        # use a subprocess to have only one thread
+        code = """if 1:
+        try:
+            import fcntl
+            import sys
+            import os
+            import signal
+            import time
+
+            def handler(signum, frame):
+                pass
+
+            signal.signal(signal.SIGALRM, handler)
+            read, write = os.pipe()
+            for fd in (read, write):
+                flags = fcntl.fcntl(fd, fcntl.F_GETFL, 0)
+                flags = flags | os.O_NONBLOCK
+                fcntl.fcntl(fd, fcntl.F_SETFL, flags)
+
+            # set wakeup_fd a read file descriptor to trigger the error
+            signal.set_wakeup_fd(read)
+
+            signal.alarm(1)
+            interval = sys.getswitchinterval()
+            while range(2):
+                time.sleep(interval)
+
+            os.close(read)
+            os.close(write)
+            sys.exit(0)
+        except ValueError:
+            sys.exit(-1)
+        """
+
+        assert_python_failure('-c', code)
+
     def test_wakeup_fd_early(self):
         self.check_wakeup("""def test():
             import select
diff -r bd5c74def80d Modules/signalmodule.c
--- a/Modules/signalmodule.c	Thu Oct 04 02:43:02 2012 +0200
+++ b/Modules/signalmodule.c	Wed Oct 03 22:56:21 2012 -0300
@@ -174,6 +174,11 @@
 static int
 checksignals_witharg(void * unused)
 {
+    int error = (int) unused;
+    if (error == EBADF || error == EPIPE || error == EINVAL) {
+        PyErr_Format(PyExc_ValueError, "error ocurred waking up 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;