Index: Objects/fileobject.c
===================================================================
--- Objects/fileobject.c	(revision 54926)
+++ Objects/fileobject.c	(working copy)
@@ -872,8 +872,10 @@
 			  buffersize - bytesread, f->f_fp, (PyObject *)f);
 		Py_END_ALLOW_THREADS
 		if (chunksize == 0) {
-			if (!ferror(f->f_fp))
+			if (!ferror(f->f_fp)) {
+				clearerr(f->f_fp);
 				break;
+			}
 			clearerr(f->f_fp);
 			/* When in non-blocking mode, data shouldn't
 			 * be discarded if a blocking signal was