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, 23 insertions, 3 deletions

diff --git a/cpukit/rtems/src/timerserverfireafter.c b/cpukit/rtems/src/timerserverfireafter.c
index 9174459346..849de800a2 100644
--- a/cpukit/rtems/src/timerserverfireafter.c
+++ b/cpukit/rtems/src/timerserverfireafter.c
@@ -52,6 +52,7 @@ rtems_status_code rtems_timer_server_fire_after(
 {
   Timer_Control        *the_timer;
   Objects_Locations     location;
+  ISR_Level             level;
   extern Chain_Control  _Timer_Ticks_chain;
 
   if ( !_Timer_Server )
@@ -73,9 +74,28 @@ rtems_status_code rtems_timer_server_fire_after(
 
     case OBJECTS_LOCAL:
       (void) _Watchdog_Remove( &the_timer->Ticker );
-      the_timer->the_class = TIMER_INTERVAL_ON_TASK;
-      _Watchdog_Initialize( &the_timer->Ticker, routine, id, user_data );
-      the_timer->Ticker.initial = ticks;
+
+      _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_ON_TASK;
+        _Watchdog_Initialize( &the_timer->Ticker, routine, id, user_data );
+        the_timer->Ticker.initial = ticks;
+      _ISR_Enable( level );
 
       _Timer_Server_stop_ticks_timer();
       _Timer_Server_process_ticks_chain();