diff --git a/include/nuttx/kmalloc.h b/include/nuttx/kmalloc.h
index 9ea6916d0b..334b2186f3 100644
--- a/include/nuttx/kmalloc.h
+++ b/include/nuttx/kmalloc.h
@@ -123,6 +123,11 @@ extern "C"
 
 FAR void *group_malloc(FAR struct task_group_s *group, size_t nbytes);
 
+/* Functions defined in group/group_realloc.c *******************************/
+
+FAR void *group_realloc(FAR struct task_group_s *group, FAR void *oldmem,
+                        size_t newsize);
+
 /* Functions defined in group/group_zalloc.c ********************************/
 
 FAR void *group_zalloc(FAR struct task_group_s *group, size_t nbytes);
@@ -136,9 +141,10 @@ void group_free(FAR struct task_group_s *group, FAR void *mem);
    * in privileges.
    */
 
-#  define group_malloc(g,n) kumm_malloc(n)
-#  define group_zalloc(g,n) kumm_zalloc(n)
-#  define group_free(g,m)   kumm_free(m)
+#  define group_malloc(g,n)      kumm_malloc(n)
+#  define group_realloc(g,p,s)   kumm_realloc((p),(s))
+#  define group_zalloc(g,n)      kumm_zalloc(n)
+#  define group_free(g,m)        kumm_free(m)
 
 #endif
 
diff --git a/sched/environ/env_dup.c b/sched/environ/env_dup.c
index 5d0df69bbd..a337e62a2e 100644
--- a/sched/environ/env_dup.c
+++ b/sched/environ/env_dup.c
@@ -94,7 +94,7 @@ int env_dup(FAR struct task_group_s *group)
         {
           /* There is an environment, duplicate it */
 
-          envp = (FAR char *)kumm_malloc(envlen);
+          envp = (FAR char *)group_malloc(ptcb->group, envlen);
           if (envp == NULL)
             {
               /* The parent's environment can not be inherited due to a
diff --git a/sched/environ/env_release.c b/sched/environ/env_release.c
index 86442dc941..412e2661a4 100644
--- a/sched/environ/env_release.c
+++ b/sched/environ/env_release.c
@@ -69,7 +69,7 @@ void env_release(FAR struct task_group_s *group)
     {
       /* Free the environment */
 
-      kumm_free(group->tg_envp);
+      group_free(group, group->tg_envp);
     }
 
   /* In any event, make sure that all environment-related variables in the
diff --git a/sched/environ/env_setenv.c b/sched/environ/env_setenv.c
index 3fdc2117f8..5a959a14d0 100644
--- a/sched/environ/env_setenv.c
+++ b/sched/environ/env_setenv.c
@@ -145,7 +145,7 @@ int setenv(FAR const char *name, FAR const char *value, int overwrite)
   if (group->tg_envp)
     {
       newsize = group->tg_envsize + varlen;
-      newenvp = (FAR char *)kumm_realloc(group->tg_envp, newsize);
+      newenvp = (FAR char *)group_realloc(group, group->tg_envp, newsize);
       if (!newenvp)
         {
           ret = ENOMEM;
@@ -157,7 +157,7 @@ int setenv(FAR const char *name, FAR const char *value, int overwrite)
   else
     {
       newsize = varlen;
-      newenvp = (FAR char *)kumm_malloc(varlen);
+      newenvp = (FAR char *)group_malloc(group, varlen);
       if (!newenvp)
         {
           ret = ENOMEM;
diff --git a/sched/environ/env_unsetenv.c b/sched/environ/env_unsetenv.c
index c83646b757..2a575739e3 100644
--- a/sched/environ/env_unsetenv.c
+++ b/sched/environ/env_unsetenv.c
@@ -86,7 +86,7 @@ int unsetenv(FAR const char *name)
 
           if (group->tg_envp != NULL)
             {
-              kumm_free(group->tg_envp);
+              group_free(group, group->tg_envp);
               group->tg_envp = NULL;
             }
 
@@ -96,7 +96,9 @@ int unsetenv(FAR const char *name)
         {
           /* Reallocate the environment to reclaim a little memory */
 
-          newenvp = (FAR char *)kumm_realloc(group->tg_envp, newsize);
+          newenvp = (FAR char *)group_realloc(group, group->tg_envp,
+                                              newsize);
+
           if (newenvp == NULL)
             {
               set_errno(ENOMEM);
diff --git a/sched/group/Make.defs b/sched/group/Make.defs
index b0a2cf7e13..0fbc28183b 100644
--- a/sched/group/Make.defs
+++ b/sched/group/Make.defs
@@ -50,7 +50,7 @@ CSRCS += group_exitinfo.c
 endif
 
 ifneq ($(CONFIG_BUILD_FLAT),y)
-CSRCS += group_malloc.c group_zalloc.c group_free.c
+CSRCS += group_malloc.c group_realloc.c group_zalloc.c group_free.c
 endif
 
 # Include group build support
diff --git a/sched/group/group_realloc.c b/sched/group/group_realloc.c
new file mode 100644
index 0000000000..04c4140239
--- /dev/null
+++ b/sched/group/group_realloc.c
@@ -0,0 +1,83 @@
+/****************************************************************************
+ * sched/group/group_realloc.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <sys/types.h>
+
+#include <assert.h>
+
+#include <nuttx/sched.h>
+#include <nuttx/kmalloc.h>
+
+#include "sched/sched.h"
+#include "group/group.h"
+
+#ifdef CONFIG_MM_KERNEL_HEAP
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: group_realloc
+ *
+ * Description:
+ *   Re-allocate memory appropriate for the group type.  If the memory is
+ *   part of a privileged group, then it should be allocated so that it
+ *   is only accessible by privileged code;  Otherwise, it is a user mode
+ *   group and must be allocated so that it accessible by unprivileged
+ *   code.
+ *
+ ****************************************************************************/
+
+FAR void *group_realloc(FAR struct task_group_s *group, FAR void *oldmem,
+                        size_t newsize)
+{
+  /* A NULL group pointer means the current group */
+
+  if (group == NULL)
+    {
+      FAR struct tcb_s *tcb = this_task();
+      DEBUGASSERT(tcb && tcb->group);
+      group = tcb->group;
+    }
+
+  /* Check the group type */
+
+  if ((group->tg_flags & GROUP_FLAG_PRIVILEGED) != 0)
+    {
+      /* It is a privileged group... use the kernel mode memory allocator */
+
+      return kmm_realloc(oldmem, newsize);
+    }
+  else
+    {
+      /* This is an unprivileged group... use the user mode memory
+       * allocator.
+       */
+
+      return kumm_realloc(oldmem, newsize);
+    }
+}
+
+#endif /* CONFIG_MM_KERNEL_HEAP */
diff --git a/sched/init/nx_start.c b/sched/init/nx_start.c
index 7938ce38de..ba8a239964 100644
--- a/sched/init/nx_start.c
+++ b/sched/init/nx_start.c
@@ -558,7 +558,8 @@ void nx_start(void)
        */
 
       group_initialize(&g_idletcb[i]);
-      g_idletcb[i].cmn.group->tg_flags = GROUP_FLAG_NOCLDWAIT;
+      g_idletcb[i].cmn.group->tg_flags = GROUP_FLAG_NOCLDWAIT |
+                                         GROUP_FLAG_PRIVILEGED;
     }
 
   g_lastpid = CONFIG_SMP_NCPUS - 1;