2005-08-17 Andrew Sinclair <Andrew.Sinclair@elprotech.com>

	PR 807/rtems
	* rtems/src/timerfireafter.c, rtems/src/timerserverfireafter.c,
	score/src/watchdoginsert.c: Tighten critical section checks on an ISR
	using the same timer being inserted by a lower priority ISR or
	interupt task.

1 files changed, 24 insertions, 2 deletions

diff --git a/cpukit/rtems/src/timerfireafter.c b/cpukit/rtems/src/timerfireafter.c
index cead1426a4..98b5d36e91 100644
--- a/cpukit/rtems/src/timerfireafter.c
+++ b/cpukit/rtems/src/timerfireafter.c
@@ -51,6 +51,7 @@ rtems_status_code rtems_timer_fire_after(
 {
   Timer_Control      *the_timer;
   Objects_Locations   location;
+  ISR_Level           level;
 
   if ( ticks == 0 )
     return RTEMS_INVALID_NUMBER;
@@ -68,8 +69,29 @@ rtems_status_code rtems_timer_fire_after(
 
     case OBJECTS_LOCAL:
       (void) _Watchdog_Remove( &the_timer->Ticker );
-      the_timer->the_class = TIMER_INTERVAL;
-      _Watchdog_Initialize( &the_timer->Ticker, routine, id, user_data );
+
+      _ISR_Disable( level );
+
+        /*
+         *  Check to see if the watchdog has just been inserted by a
+         *  higher priority interrupt.  If so, abandon this insert.
+         */
+
+        if ( the_timer->Ticker.state != WATCHDOG_INACTIVE ) {
+          _ISR_Enable( level );
+          return RTEMS_SUCCESSFUL;
+        }
+
+        /*
+         *  OK.  Now we now the timer was not rescheduled by an interrupt
+         *  so we can atomically initialize it as in use.
+         */
+
+        the_timer->the_class = TIMER_INTERVAL;
+        _Watchdog_Initialize( &the_timer->Ticker, routine, id, user_data );
+      _ISR_Enable( level );
+
+
       _Watchdog_Insert_ticks( &the_timer->Ticker, ticks );
       _Thread_Enable_dispatch();
       return RTEMS_SUCCESSFUL;