diff --git a/core/core.js b/core/core.js
index 2f8392a3..c4e266fd 100644
--- a/core/core.js
+++ b/core/core.js
@@ -13,8 +13,6 @@ let gStatsTimer = false;
 let g_handler_index = 0;
 /** Whether updating accounts information is currently scheduled. */
 let g_update_accounts_scheduled;
-/** Time between pings, in milliseconds. */
-const k_ping_interval = 60 * 1000;
 
 /**
  ** App constructor.
@@ -219,7 +217,7 @@ function postMessageInternal(from, to, message) {
  * @param options Other options.
  * @return The process.
  */
-async function getProcessBlob(blobId, key, options) {
+exports.getProcessBlob = async function getProcessBlob(blobId, key, options) {
 	let process = gProcesses[key];
 	if (!process && !(options && 'create' in options && !options.create)) {
 		let resolveReady;
@@ -239,7 +237,6 @@ async function getProcessBlob(blobId, key, options) {
 			}
 			process.lastActive = Date.now();
 			process.lastPing = null;
-			process.timeout = k_ping_interval;
 			process.ready = new Promise(function (resolve, reject) {
 				resolveReady = resolve;
 				rejectReady = reject;
@@ -692,16 +689,7 @@ async function getProcessBlob(blobId, key, options) {
 		}
 	}
 	return process;
-}
-
-/**
- * Get or create a process for an app blob.
- * @param blobId The blob identifier.
- * @param key A unique key for the invocation.
- * @param options Other options.
- * @return The process.
- */
-exports.getProcessBlob = getProcessBlob;
+};
 
 /**
  * Send any changed account information.
diff --git a/src/httpd.app.c b/src/httpd.app.c
index bb6279e8..84d42ebe 100644
--- a/src/httpd.app.c
+++ b/src/httpd.app.c
@@ -237,16 +237,19 @@ static void _httpd_auth_query_work(tf_ssb_t* ssb, void* user_data)
 static void _httpd_app_kill_task(app_t* work)
 {
 	JSContext* context = work->request->context;
-	if (!JS_IsUndefined(work->process))
+	if (JS_IsObject(work->process))
 	{
 		JSValue task = JS_GetPropertyStr(context, work->process, "task");
-		if (!JS_IsUndefined(task))
+		if (JS_IsObject(task))
 		{
 			JSValue kill = JS_GetPropertyStr(context, task, "kill");
-			JSValue result = JS_Call(context, kill, task, 0, NULL);
-			tf_util_report_error(context, result);
-			JS_FreeValue(context, result);
-			JS_FreeValue(context, kill);
+			if (!JS_IsUndefined(kill))
+			{
+				JSValue result = JS_Call(context, kill, task, 0, NULL);
+				tf_util_report_error(context, result);
+				JS_FreeValue(context, result);
+				JS_FreeValue(context, kill);
+			}
 		}
 		JS_FreeValue(context, task);
 	}
diff --git a/src/util.js.c b/src/util.js.c
index a6cb3689..173516a0 100644
--- a/src/util.js.c
+++ b/src/util.js.c
@@ -227,14 +227,12 @@ bool tf_util_report_error(JSContext* context, JSValue value)
 		tf_printf("ERROR: %s\n", string);
 		JS_FreeCString(context, string);
 
-		JSValue stack = JS_GetPropertyStr(context, value, "stack");
-		if (!JS_IsUndefined(stack))
+		const char* stack = tf_util_get_property_as_string(context, value, "stack");
+		if (stack && *stack)
 		{
-			const char* stack_str = JS_ToCString(context, stack);
-			tf_printf("%s\n", stack_str);
-			JS_FreeCString(context, stack_str);
+			tf_printf("%s\n", stack);
 		}
-		JS_FreeValue(context, stack);
+		JS_FreeCString(context, stack);
 
 		tf_task_send_error_to_parent(task, value);
 		is_error = true;