--- python3.2-3.2~a3_orig/Modules/_io/bytesio.c	2010-11-20 12:28:03.149804504 +0100
+++ python3.2-3.2~a3/Modules/_io/bytesio.c	2010-11-20 12:35:20.341804504 +0100
@@ -441,4 +441,7 @@
         len = self->string_size - self->pos;
 
+    if (len < 0)
+        len = 0;
+
     memcpy(raw_buffer, self->buf + self->pos, len);
     assert(self->pos + len < PY_SSIZE_T_MAX);