diff --git a/runtime/src/libc/syscall.c b/runtime/src/libc/syscall.c
index 7f89454..c2090a0 100644
--- a/runtime/src/libc/syscall.c
+++ b/runtime/src/libc/syscall.c
@@ -584,7 +584,7 @@ wasm_fcntl(uint32_t fd, uint32_t cmd, uint32_t arg_or_lock_ptr)
 	case WF_SETLK:
 		return 0;
 	default:
-		assert(0);
+		panic("Unexpected Command");
 	}
 }