From ad53cabf343c72329864d22f976eb12f6cb916a9 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Wed, 27 Aug 2014 09:37:28 -0600
Subject: [PATCH] ADDRENV: Use a group flag to determine if there is an address
 environment (instead of the thread type)

---
 binfmt/binfmt_execmodule.c  |  4 ++++
 include/nuttx/sched.h       |  1 +
 sched/group/group_addrenv.c | 23 +++++++++++++++--------
 sched/group/group_leave.c   |  4 ++++
 4 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/binfmt/binfmt_execmodule.c b/binfmt/binfmt_execmodule.c
index 5d49acf747..07c5072336 100644
--- a/binfmt/binfmt_execmodule.c
+++ b/binfmt/binfmt_execmodule.c
@@ -215,6 +215,10 @@ int exec_module(FAR const struct binary_s *binp)
       bdbg("ERROR: up_addrenv_clone() failed: %d\n", ret);
       goto errout_with_stack;
     }
+
+  /* Mark that this group has an address environment */
+
+  tcb->cmn.group->tg_flags |= GROUP_FLAG_ADDRENV;
 #endif
 
 #ifdef CONFIG_BINFMT_CONSTRUCTORS
diff --git a/include/nuttx/sched.h b/include/nuttx/sched.h
index 7a4004d9a8..ecff5de230 100644
--- a/include/nuttx/sched.h
+++ b/include/nuttx/sched.h
@@ -133,6 +133,7 @@
 /* Values for struct task_group tg_flags */
 
 #define GROUP_FLAG_NOCLDWAIT       (1 << 0) /* Bit 0: Do not retain child exit status */
+#define GROUP_FLAG_ADDRENV         (1 << 1) /* Bit 1: Group has an address environment */
 
 /* Values for struct child_status_s ch_flags */
 
diff --git a/sched/group/group_addrenv.c b/sched/group/group_addrenv.c
index 48e61fd4a3..35dcab9cab 100644
--- a/sched/group/group_addrenv.c
+++ b/sched/group/group_addrenv.c
@@ -110,16 +110,22 @@ int group_addrenv(FAR struct tcb_s *tcb)
   DEBUGASSERT(tcb && tcb->group);
   group = tcb->group;
 
-  /* What is the ID of the group of the new thread to run?  Use zero if the
-   * group is a kernel thread.
-   */
+  /* Does the group have an address environment? */
 
-  gid = 0;
-  if ((tcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_KERNEL)
+  if ((group->tg_flags & GROUP_FLAG_ADDRENV) == 0)
     {
-      gid = group->tg_gid;
+      /* No... just return perhaps leaving a different address environment
+       * intact.
+       */
+
+      return OK;
     }
 
+  /* Get the ID of the group that needs the address environment */
+
+  gid = group->tg_gid;
+  DEBUGASSERT(gid != 0);
+
   /* Are we going to change address environments? */
 
   flags = irqsave();
@@ -129,10 +135,11 @@ int group_addrenv(FAR struct tcb_s *tcb)
 
       if (g_gid_current != 0)
         {
-          /* Find the old group this this ID */
+          /* Find the old group with this ID. */
 
           oldgroup = group_findbygid(g_gid_current);
-          DEBUGASSERT(oldgroup);
+          DEBUGASSERT(oldgroup &&
+                     (oldgroup->tg_flags & GROUP_FLAG_ADDRENV) != 0);
 
           if (oldgroup)
             {
diff --git a/sched/group/group_leave.c b/sched/group/group_leave.c
index e3606f2eeb..403fe4c95c 100644
--- a/sched/group/group_leave.c
+++ b/sched/group/group_leave.c
@@ -212,6 +212,10 @@ static inline void group_release(FAR struct task_group_s *group)
   /* Destroy the group address environment */
 
   (void)up_addrenv_destroy(&group->addrenv);
+
+  /* Mark no address environment */
+
+  g_gid_current = 0;
 #endif
 
 #if defined(HAVE_GROUP_MEMBERS) || defined(CONFIG_ARCH_ADDRENV)