diff --git a/sched/group/group_killchildren.c b/sched/group/group_killchildren.c
index cba53ec1dab..38433122acc 100644
--- a/sched/group/group_killchildren.c
+++ b/sched/group/group_killchildren.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  *  sched/group/group_killchildren.c
  *
- *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2013, 2018 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -39,8 +39,14 @@
 
 #include <nuttx/config.h>
 
+#include <sys/types.h>
+#include <stdint.h>
 #include <sched.h>
+#include <pthread.h>
 
+#include <nuttx/sched.h>
+
+#include "sched/sched.h"
 #include "group/group.h"
 
 #ifdef HAVE_GROUP_MEMBERS
@@ -66,15 +72,34 @@
 
 static int group_killchildren_handler(pid_t pid, FAR void *arg)
 {
+  FAR struct tcb_s *rtcb;
   int ret = OK;
 
-  /* Is this the pthread that we are looking for? */
+  /* Cancel all threads except for the one specified by the argument */
 
   if (pid != (pid_t)((uintptr_t)arg))
     {
-      /* Yes.. cancel it */
+      /* Cancel this thread.  This is a forced cancellation.  Make sure that
+       * cancellation is not disabled by the task/thread.  That bit will
+       * prevent pthread_cancel() or task_delete() from doing what they need
+       * to do.
+       */
 
-      ret = pthread_cancel(pid);
+      rtcb = sched_gettcb(pid);
+      rtcb->flags &= ~TCB_FLAG_NONCANCELABLE;
+
+      /* 'pid' could refer to the main task of the thread.  That pid will
+       * appear in the group member list as well!
+       */
+
+      if ((rtcb->flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_PTHREAD)
+        {
+          ret = pthread_cancel(pid);
+        }
+       else
+        {
+          ret = task_delete(pid);
+        }
     }
 
   return ret;
diff --git a/sched/signal/sig_default.c b/sched/signal/sig_default.c
index 72303131d1b..c13ed89f2b7 100644
--- a/sched/signal/sig_default.c
+++ b/sched/signal/sig_default.c
@@ -39,7 +39,10 @@
 
 #include <nuttx/config.h>
 
+#include <stdint.h>
+#include <stdlib.h>
 #include <string.h>
+#include <pthread.h>
 #include <signal.h>
 #include <assert.h>
 
@@ -155,17 +158,41 @@ static const struct nxsig_defaction_s g_defactions[] =
 
 static void nxsig_abnormal_termination(int signo)
 {
+  FAR struct tcb_s *rtcb = (FAR struct tcb_s *)this_task();
+
+  /* Careful:  In the multi-threaded task, the signal may be handled on a
+   * child pthread.
+   */
+
 #ifdef HAVE_GROUP_MEMBERS
-  FAR struct task_tcb_s *tcb = (FAR struct task_tcb_s *)this_task();
+  /* Kill of of the children of the task.  If we are running on a pthread,
+   * this will not kill the currently running task/pthread (this_task).  It
+   * will kill the main thread of the task group if the this_task is a
+   * pthread.
+   */
 
-  /* Kill of of the children of the task */
-
-  group_killchildren(tcb);
+  group_killchildren((FAR struct task_tcb_s *)rtcb);
 #endif
 
-  /* And exit to terminate the task (note exit() vs. _exit() is used. */
+#ifndef CONFIG_DISABLE_PTHREAD
+  /* Check if the currently running task is actually a pthread */
 
-  exit(EXIT_FAILURE);
+  if ((rtcb->flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_PTHREAD)
+    {
+      /* Exit the final thread of the task group.
+       *
+       * REVISIT:  This will not work if HAVE_GROUP_MEMBERS is not set.
+       */
+
+      pthread_exit(NULL);
+    }
+  else
+#endif
+    {
+      /* Exit to terminate the task (note that exit() vs. _exit() is used. */
+
+      exit(EXIT_FAILURE);
+    }
 }
 
 /****************************************************************************