Index: Objects/fileobject.c
===================================================================
--- Objects/fileobject.c	(revision 77873)
+++ Objects/fileobject.c	(working copy)
@@ -1056,7 +1056,7 @@
 		chunksize = Py_UniversalNewlineFread(BUF(v) + bytesread,
 			  buffersize - bytesread, f->f_fp, (PyObject *)f);
 		FILE_END_ALLOW_THREADS(f)
-		if (chunksize == 0) {
+		if (errno || chunksize == 0) {
 			if (!ferror(f->f_fp))
 				break;
 			clearerr(f->f_fp);
@@ -1611,7 +1611,7 @@
 			FILE_END_ALLOW_THREADS(f)
 			shortread = (nread < buffersize-nfilled);
 		}
-		if (nread == 0) {
+		if (errno || nread == 0) {
 			sizehint = 0;
 			if (!ferror(f->f_fp))
 				break;