From 2cc001a15a86b123044369845929d5dee3e4c9bb Mon Sep 17 00:00:00 2001
From: Sebastian Huber <sebastian.huber@embedded-brains.de>
Date: Sun, 20 Dec 2015 21:47:12 +0100
Subject: score: Fix watchdog removal

Under certain conditions a new watchdog was inserted with a wrong and
very large delta interval due to an incomplete iterator update.

Bug was introduced by 1ccbd052910ed16131c74b0d5595c8a94066942d.

Close #2501.
---
 cpukit/score/src/watchdogremove.c    | 11 ++++++-
 testsuites/sptests/spwatchdog/init.c | 62 +++++++++++++++++++++++++++++++++---
 2 files changed, 67 insertions(+), 6 deletions(-)

diff --git a/cpukit/score/src/watchdogremove.c b/cpukit/score/src/watchdogremove.c
index 03c0c5f0fe..2aa72a4e75 100644
--- a/cpukit/score/src/watchdogremove.c
+++ b/cpukit/score/src/watchdogremove.c
@@ -61,7 +61,16 @@ static void _Watchdog_Remove_it(
     }
 
     if ( iterator->current == &the_watchdog->Node ) {
-      iterator->current = _Chain_Previous( &the_watchdog->Node );
+      Chain_Node *previous = _Chain_Previous( &the_watchdog->Node );
+
+      iterator->current = previous;
+
+      if ( previous != _Chain_Head( &header->Watchdogs ) ) {
+        Watchdog_Control *previous_watchdog;
+
+        previous_watchdog = (Watchdog_Control *) previous;
+        iterator->delta_interval += previous_watchdog->delta_interval;
+      }
     }
 
     iterator_node = _Chain_Next( iterator_node );
diff --git a/testsuites/sptests/spwatchdog/init.c b/testsuites/sptests/spwatchdog/init.c
index b96b680e74..d99c558d43 100644
--- a/testsuites/sptests/spwatchdog/init.c
+++ b/testsuites/sptests/spwatchdog/init.c
@@ -36,7 +36,7 @@ static void test_watchdog_routine( Objects_Id id, void *arg )
 
 static void init_watchdogs(
   Watchdog_Header *header,
-  Watchdog_Control watchdogs[3]
+  Watchdog_Control watchdogs[4]
 )
 {
   Watchdog_Control *a = &watchdogs[0];
@@ -105,23 +105,23 @@ static void test_watchdog_insert_and_remove( void )
 
   /* Remove next watchdog of iterator */
   _Watchdog_Remove( &header, c );
-  rtems_test_assert( i.delta_interval == 2 );
+  rtems_test_assert( i.delta_interval == 4 );
   rtems_test_assert( i.current == &b->Node );
 
   /* Remove watchdog before the current watchdog of iterator */
   _Watchdog_Remove( &header, a );
-  rtems_test_assert( i.delta_interval == 4 );
+  rtems_test_assert( i.delta_interval == 6 );
   rtems_test_assert( i.current == &b->Node );
 
   /* Remove current (= last) watchdog of iterator */
   _Watchdog_Remove( &header, b );
-  rtems_test_assert( i.delta_interval == 4 );
+  rtems_test_assert( i.delta_interval == 6 );
   rtems_test_assert( i.current == _Chain_Head( &header.Watchdogs ) );
 
   /* Insert first watchdog */
   a->initial = 1;
   _Watchdog_Insert( &header, a );
-  rtems_test_assert( i.delta_interval == 4 );
+  rtems_test_assert( i.delta_interval == 6 );
   rtems_test_assert( i.current == _Chain_Head( &header.Watchdogs ) );
 
   destroy_watchdogs( &header );
@@ -147,6 +147,57 @@ static void test_watchdog_insert_and_remove( void )
   destroy_watchdogs( &header );
 }
 
+static void init_watchdogs_remove_second_and_insert_first(
+  Watchdog_Header *header,
+  Watchdog_Control watchdogs[3]
+)
+{
+  Watchdog_Control *a = &watchdogs[0];
+  Watchdog_Control *b = &watchdogs[1];
+  Watchdog_Control *c = &watchdogs[2];
+
+  _Watchdog_Preinitialize( a );
+  _Watchdog_Preinitialize( b );
+  _Watchdog_Preinitialize( c );
+
+  _Watchdog_Header_initialize( header );
+
+  a->initial = 6;
+  _Watchdog_Insert( header, a );
+  rtems_test_assert( a->delta_interval == 6 );
+
+  b->initial = 8;
+  _Watchdog_Insert( header, b );
+  rtems_test_assert( a->delta_interval == 6 );
+  rtems_test_assert( b->delta_interval == 2 );
+}
+
+static void test_watchdog_remove_second_and_insert_first( void )
+{
+  Watchdog_Header header;
+  Watchdog_Control watchdogs[3];
+  Watchdog_Control *a = &watchdogs[0];
+  Watchdog_Control *b = &watchdogs[1];
+  Watchdog_Control *c = &watchdogs[2];
+  Watchdog_Iterator i;
+
+  init_watchdogs_remove_second_and_insert_first( &header, watchdogs );
+  add_iterator( &header, &i, b );
+
+  _Watchdog_Remove( &header, b );
+  rtems_test_assert( i.delta_interval == 8 );
+  rtems_test_assert( i.current == &a->Node );
+
+  c->initial = 4;
+  _Watchdog_Insert( &header, c );
+  rtems_test_assert( a->delta_interval == 2 );
+  rtems_test_assert( c->delta_interval == 4 );
+  rtems_test_assert( i.delta_interval == 4 );
+  rtems_test_assert( i.current == &a->Node );
+
+  destroy_watchdogs( &header );
+}
+
 static void test_watchdog_static_init( void )
 {
   #if defined(RTEMS_USE_16_BIT_OBJECT)
@@ -184,6 +235,7 @@ rtems_task Init(
 
   test_watchdog_static_init();
   test_watchdog_insert_and_remove();
+  test_watchdog_remove_second_and_insert_first();
 
   build_time( &time, 12, 31, 1988, 9, 0, 0, 0 );
 
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