From 0a7e136a5a674fec18bb5ceeb4e4f588f99b2ea1 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Thu, 11 Feb 2016 08:01:09 -0600
Subject: [PATCH] SMP: Idle thread must be assigned to a CPU

---
 sched/init/os_smpstart.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/sched/init/os_smpstart.c b/sched/init/os_smpstart.c
index 0bd33ffb8e..bfbc49d509 100644
--- a/sched/init/os_smpstart.c
+++ b/sched/init/os_smpstart.c
@@ -46,14 +46,11 @@
 #include <nuttx/arch.h>
 #include <nuttx/kmalloc.h>
 
+# include "sched/sched.h"
 # include "init/init.h"
 
 #ifdef CONFIG_SMP
 
-/****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
-
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -75,6 +72,23 @@
 
 int os_idletask(int argc, FAR char *argv[])
 {
+  FAR struct tcb_s *rtcb = this_task();
+  irqstate_t flags;
+  int cpu = this_cpu();
+
+  /* Make sure that this thread is assigned to the current CPU */
+
+  DEBUGASSERT(rtcb->cpu == cpu);
+
+  /* REVISIT: disabling interrupts is not sufficient protection */
+
+  flags        = irqsave();
+  rtcb->flags |= TCB_FLAG_CPU_ASSIGNED;
+  rtcb->cpu    = cpu;
+  irqrestore(flags);
+
+  /* Then enter the IDLE loop */
+
   sdbg("CPU%d: Beginning Idle Loop\n");
   for (; ; )
     {