diff --git a/include/nuttx/sched.h b/include/nuttx/sched.h
index b19cf6898e9..54e11b7c930 100644
--- a/include/nuttx/sched.h
+++ b/include/nuttx/sched.h
@@ -103,9 +103,10 @@
 #  define TCB_FLAG_SCHED_SPORADIC  (2 << TCB_FLAG_POLICY_SHIFT)  /* Sporadic scheding policy */
 #  define TCB_FLAG_SCHED_OTHER     (3 << TCB_FLAG_POLICY_SHIFT)  /* Other scheding policy */
 #define TCB_FLAG_CPU_LOCKED        (1 << 7)                      /* Bit 7: Locked to this CPU */
-#define TCB_FLAG_SIGNAL_ACTION     (1 << 8)                      /* Bit 8: In a signal handler */
-#define TCB_FLAG_SYSCALL           (1 << 9)                      /* Bit 9: In a system call */
-#define TCB_FLAG_EXIT_PROCESSING   (1 << 10)                     /* Bit 10: Exitting */
+#define TCB_FLAG_CUSTOM_STACK      (1 << 8)                      /* Bit 8: Thread uses a custom stack */
+#define TCB_FLAG_SIGNAL_ACTION     (1 << 9)                      /* Bit 9: In a signal handler */
+#define TCB_FLAG_SYSCALL           (1 << 10)                     /* Bit 10: In a system call */
+#define TCB_FLAG_EXIT_PROCESSING   (1 << 11)                     /* Bit 11: Exitting */
                                                                  /* Bits 11-15: Available */
 
 /* Values for struct task_group tg_flags */
@@ -920,6 +921,14 @@ FAR struct socketlist *nxsched_get_sockets(void);
  *     2. Allocate the stack.  The pre-allocated stack is passed in argv.
  *     3. Activate the task. This must be done by calling nxtask_activate().
  *
+ *   Certain fields of the pre-allocated TCB may be set to change the
+ *   nature of the created task.  For example:
+ *
+ *     - Task type may be set in the TCB flags to create  kernel thread
+ *     - If a custom stack is used, i.e., one allocated, managed, and freed
+ *       by the caller, then TCB_FLAG_CUSTOM_STACK should be set in the
+ *       TCB flags.
+ *
  * Input Parameters:
  *   tcb        - Address of the new task's TCB
  *   name       - Name of the new task (not used)
@@ -954,6 +963,8 @@ int nxtask_init(FAR struct tcb_s *tcb, const char *name, int priority,
  *   was when a subsequent call to task_activate fails.
  *
  *   Caution:  Freeing of the TCB itself might be an unexpected side-effect.
+ *   The stack will also be freed UNLESS TCB_FLAG_CUSTOM_STACK was set in
+ *   in the tcb->flags field when nxtask_init() was called.
  *
  * Input Parameters:
  *   tcb - Address of the TCB initialized by task_init()
diff --git a/sched/sched/sched_releasetcb.c b/sched/sched/sched_releasetcb.c
index 5cf57b62828..00e6355642c 100644
--- a/sched/sched/sched_releasetcb.c
+++ b/sched/sched/sched_releasetcb.c
@@ -127,9 +127,12 @@ int nxsched_release_tcb(FAR struct tcb_s *tcb, uint8_t ttype)
           nxsched_releasepid(tcb->pid);
         }
 
-      /* Delete the thread's stack if one has been allocated */
+      /* Delete the thread's stack if one has been allocated and it is
+       * not some custom stack managed by the caller.
+       */
 
-      if (tcb->stack_alloc_ptr)
+      if (tcb->stack_alloc_ptr &&
+          (tcb->flags & TCB_FLAG_CUSTOM_STACK) == 0)
         {
 #ifdef CONFIG_BUILD_KERNEL
           /* If the exiting thread is not a kernel thread, then it has an
diff --git a/sched/task/task_init.c b/sched/task/task_init.c
index 315e6b6f6d0..91c7904b138 100644
--- a/sched/task/task_init.c
+++ b/sched/task/task_init.c
@@ -54,6 +54,14 @@
  *     2. Allocate the stack.  The pre-allocated stack is passed in argv.
  *     3. Activate the task. This must be done by calling nxtask_activate().
  *
+ *   Certain fields of the pre-allocated TCB may be set to change the
+ *   nature of the created task.  For example:
+ *
+ *     - Task type may be set in the TCB flags to create  kernel thread
+ *     - If a custom stack is used, i.e., one allocated, managed, and freed
+ *       by the caller, then TCB_FLAG_CUSTOM_STACK should be set in the
+ *       TCB flags.
+ *
  * Input Parameters:
  *   tcb        - Address of the new task's TCB
  *   name       - Name of the new task (not used)
@@ -148,6 +156,8 @@ errout:
  *   was when a subsequent call to task_activate fails.
  *
  *   Caution:  Freeing of the TCB itself might be an unexpected side-effect.
+ *   The stack will also be freed UNLESS TCB_FLAG_CUSTOM_STACK was set in
+ *   in the tcb->flags field when nxtask_init() was called.
  *
  * Input Parameters:
  *   tcb - Address of the TCB initialized by task_init()