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authorSebastian Huber <sebastian.huber@embedded-brains.de>2014-05-22 09:31:13 +0200
committerSebastian Huber <sebastian.huber@embedded-brains.de>2014-05-23 08:57:32 +0200
commit4edf348c3395560bcaaf3c020968e427f5683d28 (patch)
treebb132a0862f916a58de14df14eb32d6c7d5df20e
parentdecff888363d23dac5bfe1f10e46fb7a280eaf23 (diff)
downloadrtems-4edf348c3395560bcaaf3c020968e427f5683d28.tar.bz2
score: PR2179: Fix initially locked PCP mutexes
Elevate the priority of the creating task to the ceiling priority in case a semaphore is created as initially locked.
-rw-r--r--cpukit/score/src/coremutex.c19
-rw-r--r--testsuites/sptests/sp65/init.c35
-rw-r--r--testsuites/sptests/sp65/sp65.doc2
3 files changed, 53 insertions, 3 deletions
diff --git a/cpukit/score/src/coremutex.c b/cpukit/score/src/coremutex.c
index 96b11c9cd1..e13c7aafac 100644
--- a/cpukit/score/src/coremutex.c
+++ b/cpukit/score/src/coremutex.c
@@ -43,10 +43,20 @@ CORE_mutex_Status _CORE_mutex_Initialize(
the_mutex->holder = executing;
if ( _CORE_mutex_Is_inherit_priority( &the_mutex->Attributes ) ||
_CORE_mutex_Is_priority_ceiling( &the_mutex->Attributes ) ) {
+ Priority_Control ceiling = the_mutex->Attributes.priority_ceiling;
+
+ /*
+ * The mutex initialization is only protected by the allocator lock in
+ * general. Disable thread dispatching before the priority check to
+ * prevent interference with priority inheritance.
+ */
+ _Thread_Disable_dispatch();
+
+ if ( executing->current_priority < ceiling ) {
+ _Thread_Enable_dispatch();
+ return CORE_MUTEX_STATUS_CEILING_VIOLATED;
+ }
- if ( executing->current_priority <
- the_mutex->Attributes.priority_ceiling )
- return CORE_MUTEX_STATUS_CEILING_VIOLATED;
#ifdef __RTEMS_STRICT_ORDER_MUTEX__
_Chain_Prepend_unprotected( &executing->lock_mutex,
&the_mutex->queue.lock_queue );
@@ -54,6 +64,9 @@ CORE_mutex_Status _CORE_mutex_Initialize(
#endif
executing->resource_count++;
+
+ _Thread_Change_priority( executing, ceiling, false );
+ _Thread_Enable_dispatch();
}
} else {
the_mutex->nest_count = 0;
diff --git a/testsuites/sptests/sp65/init.c b/testsuites/sptests/sp65/init.c
index cba836d422..7c6d8d3bef 100644
--- a/testsuites/sptests/sp65/init.c
+++ b/testsuites/sptests/sp65/init.c
@@ -28,6 +28,17 @@ rtems_task Task_1(rtems_task_argument arg);
#define TASK_PRIORITY 1
#endif
+static void assert_priority(rtems_task_priority expected)
+{
+ rtems_status_code sc;
+ rtems_task_priority prio;
+
+ sc = rtems_task_set_priority(RTEMS_SELF, RTEMS_CURRENT_PRIORITY, &prio);
+ rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+
+ rtems_test_assert(prio == expected);
+}
+
rtems_task Init(
rtems_task_argument ignored
)
@@ -38,6 +49,30 @@ rtems_task Init(
TEST_BEGIN();
/*
+ * Verify that an initially locked priority ceiling mutex elevates the
+ * priority of the creating task.
+ */
+
+ status = rtems_semaphore_create(
+ rtems_build_name( 's','e','m','1' ),
+ 0,
+ RTEMS_BINARY_SEMAPHORE | RTEMS_PRIORITY | RTEMS_PRIORITY_CEILING,
+ 1,
+ &Mutex_id
+ );
+ rtems_test_assert(status == RTEMS_SUCCESSFUL);
+
+ assert_priority(1);
+
+ status = rtems_semaphore_release(Mutex_id);
+ rtems_test_assert(status == RTEMS_SUCCESSFUL);
+
+ assert_priority(TASK_PRIORITY);
+
+ status = rtems_semaphore_delete(Mutex_id);
+ rtems_test_assert(status == RTEMS_SUCCESSFUL);
+
+ /*
* Create binary semaphore (a.k.a. Mutex) with Priority Ceiling
* attribute.
*/
diff --git a/testsuites/sptests/sp65/sp65.doc b/testsuites/sptests/sp65/sp65.doc
index 73786eefc9..854dedeb07 100644
--- a/testsuites/sptests/sp65/sp65.doc
+++ b/testsuites/sptests/sp65/sp65.doc
@@ -23,3 +23,5 @@ concepts:
+ Verify the priority ceiling mutex getting released which results in a thread
being unblocked and the unblocked thread's priority being elevated.
++ Verify that an initially locked priority ceiling mutex elevates the priority
+ of the creating task.