gtphub: tweak an error log message
diff --git a/openbsc/src/gprs/gtphub.c b/openbsc/src/gprs/gtphub.c
index 132808a..6428c60 100644
--- a/openbsc/src/gprs/gtphub.c
+++ b/openbsc/src/gprs/gtphub.c
@@ -1421,7 +1421,8 @@
 	if (p->type == GTP_CREATE_PDP_REQ) {
 		if (p->side_idx != GTPH_SIDE_SGSN) {
 			LOG(LOGL_ERROR, "Wrong side: Create PDP Context"
-			    " Request from the GGSN side");
+			    " Request from the GGSN side: %s",
+			    gtphub_port_str(from_ctrl));
 			return -1;
 		}
 
@@ -1436,7 +1437,8 @@
 	} else if (p->type == GTP_CREATE_PDP_RSP) {
 		if (p->side_idx != GTPH_SIDE_GGSN) {
 			LOG(LOGL_ERROR, "Wrong side: Create PDP Context"
-			    " Response from the SGSN side");
+			    " Response from the SGSN side: %s",
+			    gtphub_port_str(from_ctrl));
 			return -1;
 		}