diff --git a/libraries/rtos/rtx/TARGET_CORTEX_M/RTX_Conf_CM.c b/libraries/rtos/rtx/TARGET_CORTEX_M/RTX_Conf_CM.c
index 178aa0f603..68a03c226e 100755
--- a/libraries/rtos/rtx/TARGET_CORTEX_M/RTX_Conf_CM.c
+++ b/libraries/rtos/rtx/TARGET_CORTEX_M/RTX_Conf_CM.c
@@ -70,8 +70,10 @@
 #      define OS_SCHEDULERSTKSIZE    256
 #  elif defined(TARGET_LPC11U24) || defined(TARGET_LPC11U35_401)  || defined(TARGET_LPC11U35_501) || defined(TARGET_LPCCAPPUCCINO)  || defined(TARGET_LPC1114) \
    || defined(TARGET_LPC812)   || defined(TARGET_KL25Z)         || defined(TARGET_KL05Z)        || defined(TARGET_STM32F100RB)  || defined(TARGET_STM32F051R8) \
-   || defined(TARGET_STM32F103RB) || defined(TARGET_LPC824) || defined(TARGET_STM32F302R8) || defined(TARGET_STM32F334R8) || defined(TARGET_STM32F334C8)
+   || defined(TARGET_STM32F103RB) || defined(TARGET_LPC824) || defined(TARGET_STM32F302R8)
 #      define OS_SCHEDULERSTKSIZE    128
+#  elif defined(TARGET_STM32F334R8) || defined(TARGET_STM32F334C8)
+#      define OS_SCHEDULERSTKSIZE    112
 #  else
 #    error "no target defined"
 #  endif