Index: Lib/json/decoder.py
===================================================================
--- Lib/json/decoder.py	(révision 65915)
+++ Lib/json/decoder.py	(copie de travail)
@@ -18,11 +18,15 @@
 
 
 def linecol(doc, pos):
-    lineno = doc.count('\n', 0, pos) + 1
+    if isinstance(doc, bytes):
+        newline = b'\n'
+    else:
+        newline = '\n'
+    lineno = doc.count(newline, 0, pos) + 1
     if lineno == 1:
         colno = pos
     else:
-        colno = pos - doc.rindex('\n', 0, pos)
+        colno = pos - doc.rindex(newline, 0, pos)
     return lineno, colno
 
 
Index: Modules/_json.c
===================================================================
--- Modules/_json.c	(révision 65915)
+++ Modules/_json.c	(copie de travail)
@@ -179,11 +179,13 @@
         errmsg_fn = PyObject_GetAttrString(decoder, "errmsg");
         if (errmsg_fn == NULL)
             return;
-        Py_XDECREF(decoder);
+        Py_DECREF(decoder);
     }
     pymsg = PyObject_CallFunction(errmsg_fn, "(zOn)", msg, s, end);
+    if (pymsg) {
     PyErr_SetObject(PyExc_ValueError, pymsg);
     Py_DECREF(pymsg);
+    }
 /*
 
 def linecol(doc, pos):
@@ -602,7 +604,7 @@
                      Py_TYPE(pystr)->tp_name);
         return NULL;
     }
-    if (PyBytes_Check(rval)) {
+    if (rval != NULL && PyBytes_Check(rval)) {
         PyObject *urval = PyUnicode_DecodeASCII(PyBytes_AS_STRING(rval), PyBytes_GET_SIZE(rval), NULL);
         Py_DECREF(rval);
         return urval;