2007-05-22 Joel Sherrill <joel.sherrill@OARcorp.com>

	* score/src/corerwlockrelease.c: Do not dereference NULL.

1 files changed, 25 insertions, 24 deletions

diff --git a/cpukit/score/src/corerwlockrelease.c b/cpukit/score/src/corerwlockrelease.c
index 30daaeaba9..b9d0e2f9e1 100644
--- a/cpukit/score/src/corerwlockrelease.c
+++ b/cpukit/score/src/corerwlockrelease.c
@@ -79,32 +79,33 @@ CORE_RWLock_Status _CORE_RWLock_Release(
 
     next = _Thread_queue_Dequeue( &the_rwlock->Wait_queue );
     
-    rwmode = next->Wait.option;
-    if ( rwmode == CORE_RWLOCK_THREAD_WAITING_FOR_WRITE ) {
-      the_rwlock->current_state = CORE_RWLOCK_LOCKED_FOR_WRITING;
-      return CORE_RWLOCK_SUCCESSFUL;
-    } 
-
-    /*
-     * Must be CORE_RWLOCK_THREAD_WAITING_FOR_READING now see if more
-     * readers can be let go.
-     */
-
-    while ( 1 ) {
-      next = _Thread_queue_First( &the_rwlock->Wait_queue );
-      if ( !next ) 
-        return CORE_RWLOCK_SUCCESSFUL;
-      if ( next->Wait.option != CORE_RWLOCK_THREAD_WAITING_FOR_READ )
-        return CORE_RWLOCK_SUCCESSFUL;
-
-      /* it is definitely wanting to read */
-      the_rwlock->number_of_readers += 1;
-      _Thread_queue_Extract( &the_rwlock->Wait_queue, next );
-    }
-
-
+    if ( next ) {
+      rwmode = next->Wait.option;
+      if ( rwmode == CORE_RWLOCK_THREAD_WAITING_FOR_WRITE ) {
+       the_rwlock->current_state = CORE_RWLOCK_LOCKED_FOR_WRITING;
+       return CORE_RWLOCK_SUCCESSFUL;
+     } 
+
+     /*
+      * Must be CORE_RWLOCK_THREAD_WAITING_FOR_READING now see if more
+      * readers can be let go.
+      */
+
+     while ( 1 ) {
+       next = _Thread_queue_First( &the_rwlock->Wait_queue );
+       if ( !next ) 
+         return CORE_RWLOCK_SUCCESSFUL;
+       if ( next->Wait.option != CORE_RWLOCK_THREAD_WAITING_FOR_READ )
+         return CORE_RWLOCK_SUCCESSFUL;
+
+       /* it is definitely wanting to read */
+       the_rwlock->number_of_readers += 1;
+       _Thread_queue_Extract( &the_rwlock->Wait_queue, next );
+     }
 
     /* XXX need to put read/write lock request indicator in Wait info */
 
+  }
+
   return CORE_RWLOCK_SUCCESSFUL;
 }