diff -r 2f46f6d9e48b Lib/test/test_file.py
--- a/Lib/test/test_file.py	Wed Mar 09 01:50:19 2011 -0500
+++ b/Lib/test/test_file.py	Wed Mar 09 02:14:45 2011 -0500
@@ -322,6 +322,48 @@
         finally:
             os.unlink(TESTFN)
 
+    def testReadAfterEOF(self):
+        def testfunc():
+            # Verify read works after hitting EOF
+
+            # Prepare the testfile
+            teststring = "spam"
+            bag = open(TESTFN, "w")
+            bag.write(teststring)
+            bag.close()
+
+            # Test for appropriate errors mixing read* and iteration
+            methods = [("readline", ()), ("read",()), ("readlines", ())]
+
+            for attr in 'r', 'rU':
+                for methodname, args in methods:
+                    f = open(TESTFN, "rU")
+                    f.seek(0, 2)
+                    meth = getattr(f, methodname)
+                    meth(*args) # hits EOF
+                    try:
+                        # Writing the same file with another file descriptor
+                        append = open(TESTFN, "a+")
+                        append.write(teststring)
+                        append.flush()
+                        append.close()
+                        try:
+                            meth = getattr(f, methodname)
+                            if methodname == 'readlines':
+                                self.assertEqual(meth(*args), [teststring])
+                            else:
+                                self.assertEqual(meth(*args), teststring)
+                        except ValueError:
+                                self.fail("read* failed after hitting EOF")
+                    finally:
+                        f.close()
+
+        try:
+            testfunc()
+        finally:
+            os.unlink(TESTFN)
+
+
 class COtherFileTests(OtherFileTests):
     open = io.open
 
diff -r 2f46f6d9e48b Lib/test/test_fileio.py
--- a/Lib/test/test_fileio.py	Wed Mar 09 01:50:19 2011 -0500
+++ b/Lib/test/test_fileio.py	Wed Mar 09 02:14:45 2011 -0500
@@ -398,6 +398,53 @@
             self.assertRaises(ValueError, _FileIO, "/some/invalid/name", "rt")
             self.assertEqual(w.warnings, [])
 
+    def testReadAfterEOF(self):
+        def testfunc():
+            # Verify read works after hitting EOF
+
+            # Prepare the testfile
+            teststring = b"spam"
+            bag = _FileIO(TESTFN, "w")
+            bag.write(teststring)
+            bag.close()
+
+            # And buf for readinto
+            buf = bytearray(len(teststring))
+
+            # Test for appropriate errors mixing read* and iteration
+            methods = [("readline", ()), ("read",()), ("readlines", ()),
+                       ("readinto", (buf,))]
+
+            for methodname, args in methods:
+                f = _FileIO(TESTFN, "r")
+                f.seek(0, 2)
+                meth = getattr(f, methodname)
+                meth(*args) # hits EOF
+                try:
+                    # Writing the same file with another file descriptor
+                    append = _FileIO(TESTFN, "a+")
+                    append.write(teststring)
+                    append.flush()
+                    append.close()
+                    try:
+                        meth = getattr(f, methodname)
+                        if methodname == 'readlines':
+                            self.assertEqual(meth(*args), [teststring])
+                        elif methodname == 'readinto':
+                            meth(*args)
+                            self.assertEqual(buf, teststring)
+                        else:
+                            self.assertEqual(meth(*args), teststring)
+                    except ValueError:
+                            self.fail("read* failed after hitting EOF")
+                finally:
+                    f.close()
+
+        try:
+            testfunc()
+        finally:
+            os.unlink(TESTFN)
+
 
 def test_main():
     # Historically, these tests have been sloppy about removing TESTFN.
diff -r 2f46f6d9e48b Objects/fileobject.c
--- a/Objects/fileobject.c	Wed Mar 09 01:50:19 2011 -0500
+++ b/Objects/fileobject.c	Wed Mar 09 02:14:45 2011 -0500
@@ -264,6 +264,7 @@
         return NULL;
     }
     FLOCKFILE(stream);
+    clearerr(stream);
     c = 'x'; /* Shut up gcc warning */
     while (--n > 0 && (c = GETC(stream)) != EOF ) {
         if (skipnextlf ) {
@@ -299,7 +300,6 @@
     }
     /* if ( c == EOF && skipnextlf )
         newlinetypes |= NEWLINE_CR; */
-    FUNLOCKFILE(stream);
     *p = '\0';
     if ( skipnextlf ) {
         /* If we have no file object we cannot save the
@@ -313,6 +313,7 @@
         if ( c != '\n' )
             ungetc(c, stream);
     }
+    FUNLOCKFILE(stream);
     if (p == buf)
         return NULL;
     return buf;