diff --git a/rtos/rtx/TARGET_CORTEX_M/RTX_CM_lib.h b/rtos/rtx/TARGET_CORTEX_M/RTX_CM_lib.h
index 241d3153e8..767f9edb11 100644
--- a/rtos/rtx/TARGET_CORTEX_M/RTX_CM_lib.h
+++ b/rtos/rtx/TARGET_CORTEX_M/RTX_CM_lib.h
@@ -426,6 +426,9 @@ extern uint32_t __StackTop[];
 #else
 #define INITIAL_SP            (0x20030000UL)
 #endif
+#if defined(__CC_ARM) || defined(__GNUC__)
+#define ISR_STACK_SIZE        (0x1000)
+#endif
 
 #elif defined(TARGET_K22F)
 #define INITIAL_SP            (0x20010000UL)