Index: main/channel.c
===================================================================
--- main/channel.c	(revision 222103)
+++ main/channel.c	(working copy)
@@ -3001,6 +3030,13 @@
 	if (chan->music_state && chan->generator && chan->generator->digit && f && f->frametype == AST_FRAME_DTMF_END)
 		chan->generator->digit(chan, f->subclass);
 
+	if (f && f->datalen==0 && f->data.ptr) {
+		ast_log(LOG_WARNING,"Found frame with datalen=0 but initialized data pointer:\n");
+		ast_frame_dump(chan->name, f, "<<");
+		/* Fix the frame */
+		f->data.ptr = NULL;
+	}
+
 	ast_channel_unlock(chan);
 	return f;
 }