int ret, chan_kern_created = 0, chan_ust_created = 0;
char *app_ctx_provider_name = NULL, *app_ctx_name = NULL;
+ /*
+ * Don't try to add a context if the session has been started at
+ * some point in time before. The tracer does not allow it and would
+ * result in a corrupted trace.
+ */
+ if (session->has_been_started) {
+ ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
+ goto end;
+ }
+
if (ctx->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT) {
app_ctx_provider_name = ctx->u.app_ctx.provider_name;
app_ctx_name = ctx->u.app_ctx.ctx_name;