diff --git a/ril/libril/ril.cpp b/ril/libril/ril.cpp
index 66dd9588..37582f00 100644
--- a/ril/libril/ril.cpp
+++ b/ril/libril/ril.cpp
@@ -4418,7 +4418,7 @@ RIL_register (const RIL_RadioFunctions *callbacks) {
 
     char rildebug[MAX_DEBUG_SOCKET_NAME_LENGTH] = SOCKET_NAME_RIL_DEBUG;
     if (inst != NULL) {
-        strncat(rildebug, inst, MAX_DEBUG_SOCKET_NAME_LENGTH);
+        snprintf(rildebug, sizeof(rildebug), "%s%s", SOCKET_NAME_RIL_DEBUG, inst);
     }
 
     s_fdDebug = android_get_control_socket(rildebug);