diff --git a/portable/ThirdParty/GCC/Posix/port.c b/portable/ThirdParty/GCC/Posix/port.c
index ff386ac9f..dd7ca1a9a 100644
--- a/portable/ThirdParty/GCC/Posix/port.c
+++ b/portable/ThirdParty/GCC/Posix/port.c
@@ -52,7 +52,7 @@
 * Note: When using LLDB (the default debugger on macOS) with this port, 
 * suppress SIGUSR1 to prevent debugger interference. This can be
 * done by adding the following line to ~/.lldbinit:
-* `process handle SIGUSR1 -n true -p true -s false`
+* `process handle SIGUSR1 -n true -p false -s false`
 *----------------------------------------------------------*/
 #ifdef __linux__
     #define _GNU_SOURCE
@@ -384,6 +384,10 @@ static void prvPortYieldFromISR( void )
 
 void vPortYield( void )
 {
+    /* This must never be called from outside of a FreeRTOS-owned thread, or
+     * the thread could get stuck in a suspended state. */
+    configASSERT( prvIsFreeRTOSThread() == pdTRUE );
+
     vPortEnterCritical();
 
     prvPortYieldFromISR();