diff --git a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0/TOOLCHAIN_GCC/HAL_CM0.s b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0/TOOLCHAIN_GCC/HAL_CM0.s
index 416b8279b8..a7dd8d460f 100644
--- a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0/TOOLCHAIN_GCC/HAL_CM0.s
+++ b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0/TOOLCHAIN_GCC/HAL_CM0.s
@@ -35,7 +35,7 @@
         .file   "HAL_CM0.S"
         .syntax unified
 
-        .equ    TCB_TSTACK, 36
+        .equ    TCB_TSTACK, 40
 
 
 /*----------------------------------------------------------------------------
diff --git a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0/TOOLCHAIN_IAR/HAL_CM0.s b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0/TOOLCHAIN_IAR/HAL_CM0.s
index 5aa21f38c2..000b82ad48 100644
--- a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0/TOOLCHAIN_IAR/HAL_CM0.s
+++ b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0/TOOLCHAIN_IAR/HAL_CM0.s
@@ -34,7 +34,7 @@
 
         NAME    HAL_CM0.S
 
-        #define TCB_TSTACK 36
+        #define TCB_TSTACK 40
 
         EXTERN  os_flags
         EXTERN  os_tsk
diff --git a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0P/TOOLCHAIN_GCC/HAL_CM0.s b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0P/TOOLCHAIN_GCC/HAL_CM0.s
index 416b8279b8..a7dd8d460f 100644
--- a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0P/TOOLCHAIN_GCC/HAL_CM0.s
+++ b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0P/TOOLCHAIN_GCC/HAL_CM0.s
@@ -35,7 +35,7 @@
         .file   "HAL_CM0.S"
         .syntax unified
 
-        .equ    TCB_TSTACK, 36
+        .equ    TCB_TSTACK, 40
 
 
 /*----------------------------------------------------------------------------
diff --git a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0P/TOOLCHAIN_IAR/HAL_CM0.s b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0P/TOOLCHAIN_IAR/HAL_CM0.s
index 5aa21f38c2..000b82ad48 100644
--- a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0P/TOOLCHAIN_IAR/HAL_CM0.s
+++ b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M0P/TOOLCHAIN_IAR/HAL_CM0.s
@@ -34,7 +34,7 @@
 
         NAME    HAL_CM0.S
 
-        #define TCB_TSTACK 36
+        #define TCB_TSTACK 40
 
         EXTERN  os_flags
         EXTERN  os_tsk
diff --git a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M3/TOOLCHAIN_GCC/HAL_CM3.s b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M3/TOOLCHAIN_GCC/HAL_CM3.s
index 4b27f20928..42081d3ee8 100644
--- a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M3/TOOLCHAIN_GCC/HAL_CM3.s
+++ b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M3/TOOLCHAIN_GCC/HAL_CM3.s
@@ -35,7 +35,7 @@
         .file   "HAL_CM3.S"
         .syntax unified
 
-        .equ    TCB_TSTACK, 36
+        .equ    TCB_TSTACK, 40
 
 
 /*----------------------------------------------------------------------------
diff --git a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M3/TOOLCHAIN_IAR/HAL_CM3.s b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M3/TOOLCHAIN_IAR/HAL_CM3.s
index e6fcbc5136..b8bb983c10 100644
--- a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M3/TOOLCHAIN_IAR/HAL_CM3.s
+++ b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M3/TOOLCHAIN_IAR/HAL_CM3.s
@@ -34,7 +34,7 @@
 
         NAME    HAL_CM3.S
 
-        #define TCB_TSTACK 36
+        #define TCB_TSTACK 40
 
         EXTERN  os_flags
         EXTERN  os_tsk
diff --git a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M4/TOOLCHAIN_GCC/HAL_CM4.s b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M4/TOOLCHAIN_GCC/HAL_CM4.s
index 0208a74a2c..e648458481 100644
--- a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M4/TOOLCHAIN_GCC/HAL_CM4.s
+++ b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M4/TOOLCHAIN_GCC/HAL_CM4.s
@@ -36,7 +36,7 @@
         .syntax unified
 
         .equ    TCB_STACKF, 32
-        .equ    TCB_TSTACK, 36
+        .equ    TCB_TSTACK, 40
 
 
 /*----------------------------------------------------------------------------
diff --git a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M4/TOOLCHAIN_IAR/HAL_CM4.s b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M4/TOOLCHAIN_IAR/HAL_CM4.s
index c6afbd64ae..7ae276f6b3 100644
--- a/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M4/TOOLCHAIN_IAR/HAL_CM4.s
+++ b/libraries/rtos/rtx/TARGET_CORTEX_M/TARGET_M4/TOOLCHAIN_IAR/HAL_CM4.s
@@ -35,7 +35,7 @@
         NAME    HAL_CM4.S
 
         #define TCB_STACKF 32
-        #define TCB_TSTACK 36
+        #define TCB_TSTACK 40
 
         EXTERN  os_flags
         EXTERN  os_tsk
diff --git a/libraries/rtos/rtx/TARGET_CORTEX_M/os_tcb.h b/libraries/rtos/rtx/TARGET_CORTEX_M/os_tcb.h
index 9e18b285eb..800f7f534a 100644
--- a/libraries/rtos/rtx/TARGET_CORTEX_M/os_tcb.h
+++ b/libraries/rtos/rtx/TARGET_CORTEX_M/os_tcb.h
@@ -32,8 +32,9 @@ typedef struct OS_TCB {
 
   /* Hardware dependant part: specific for CM processor                      */
   U8     stack_frame;             /* Stack frame: 0=Basic, 1=Extended        */
-  U8     reserved;
-  U16    priv_stack;              /* Private stack size in bytes             */
+  U8     reserved1;
+  U16    reserved2;
+  U32    priv_stack;              /* Private stack size in bytes             */
   U32    tsk_stack;               /* Current task Stack pointer (R13)        */
   U32    *stack;                  /* Pointer to Task Stack memory block      */
 
diff --git a/libraries/rtos/rtx/TARGET_CORTEX_M/rt_TypeDef.h b/libraries/rtos/rtx/TARGET_CORTEX_M/rt_TypeDef.h
index 2adbe88cd8..27416c502c 100644
--- a/libraries/rtos/rtx/TARGET_CORTEX_M/rt_TypeDef.h
+++ b/libraries/rtos/rtx/TARGET_CORTEX_M/rt_TypeDef.h
@@ -41,7 +41,7 @@ typedef void    *OS_ID;
 typedef U32     OS_RESULT;
 
 #define TCB_STACKF      32        /* 'stack_frame' offset                    */
-#define TCB_TSTACK      36        /* 'tsk_stack' offset                      */
+#define TCB_TSTACK      40        /* 'tsk_stack' offset                      */
 
 typedef struct OS_PSFE {          /* Post Service Fifo Entry                 */
   void  *id;                      /* Object Identification                   */