3 files changed, 40 insertions, 6 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index b4e6be7de5ad..821f0481ebe1 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1044,11 +1044,13 @@ extern void sched_idle_next(void);
 #ifdef CONFIG_RT_MUTEXES
 extern int rt_mutex_getprio(task_t *p);
 extern void rt_mutex_setprio(task_t *p, int prio);
+extern void rt_mutex_adjust_pi(task_t *p);
 #else
 static inline int rt_mutex_getprio(task_t *p)
 {
         return p->normal_prio;
 }
+# define rt_mutex_adjust_pi(p)          do { } while (0)
 #endif
 
 extern void set_user_nice(task_t *p, long nice);
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index 3fc0f0680ca2..45d61016da57 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -160,7 +160,8 @@ int max_lock_depth = 1024;
 static int rt_mutex_adjust_prio_chain(task_t *task,
                                       int deadlock_detect,
                                       struct rt_mutex *orig_lock,
-                                      struct rt_mutex_waiter *orig_waiter
+                                      struct rt_mutex_waiter *orig_waiter,
+                                      struct task_struct *top_task
                                       __IP_DECL__)
 {
         struct rt_mutex *lock;
@@ -189,7 +190,7 @@ static int rt_mutex_adjust_prio_chain(task_t *task,
                         prev_max = max_lock_depth;
                         printk(KERN_WARNING "Maximum lock depth %d reached "
                                "task: %s (%d)\n", max_lock_depth,
-                               current->comm, current->pid);
+                               top_task->comm, top_task->pid);
                 }
                 put_task_struct(task);
 
@@ -229,7 +230,7 @@ static int rt_mutex_adjust_prio_chain(task_t *task,
         }
 
         /* Deadlock detection */
-        if (lock == orig_lock || rt_mutex_owner(lock) == current) {
+        if (lock == orig_lock || rt_mutex_owner(lock) == top_task) {
                 debug_rt_mutex_deadlock(deadlock_detect, orig_waiter, lock);
                 spin_unlock(&lock->wait_lock);
                 ret = deadlock_detect ? -EDEADLK : 0;
@@ -433,6 +434,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
                 __rt_mutex_adjust_prio(owner);
                 if (owner->pi_blocked_on) {
                         boost = 1;
+                        /* gets dropped in rt_mutex_adjust_prio_chain()! */
                         get_task_struct(owner);
                 }
                 spin_unlock_irqrestore(&owner->pi_lock, flags);
@@ -441,6 +443,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
                 spin_lock_irqsave(&owner->pi_lock, flags);
                 if (owner->pi_blocked_on) {
                         boost = 1;
+                        /* gets dropped in rt_mutex_adjust_prio_chain()! */
                         get_task_struct(owner);
                 }
                 spin_unlock_irqrestore(&owner->pi_lock, flags);
@@ -450,8 +453,8 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
 
         spin_unlock(&lock->wait_lock);
 
-        res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock,
-                                         waiter __IP__);
+        res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, waiter,
+                                         current __IP__);
 
         spin_lock(&lock->wait_lock);
 
@@ -552,6 +555,7 @@ static void remove_waiter(struct rt_mutex *lock,
 
                 if (owner->pi_blocked_on) {
                         boost = 1;
+                        /* gets dropped in rt_mutex_adjust_prio_chain()! */
                         get_task_struct(owner);
                 }
                 spin_unlock_irqrestore(&owner->pi_lock, flags);
@@ -564,12 +568,37 @@ static void remove_waiter(struct rt_mutex *lock,
 
         spin_unlock(&lock->wait_lock);
 
-        rt_mutex_adjust_prio_chain(owner, 0, lock, NULL __IP__);
+        rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current __IP__);
 
         spin_lock(&lock->wait_lock);
 }
 
 /*
+ * Recheck the pi chain, in case we got a priority setting
+ *
+ * Called from sched_setscheduler
+ */
+void rt_mutex_adjust_pi(struct task_struct *task)
+{
+        struct rt_mutex_waiter *waiter;
+        unsigned long flags;
+
+        spin_lock_irqsave(&task->pi_lock, flags);
+
+        waiter = task->pi_blocked_on;
+        if (!waiter || waiter->list_entry.prio == task->prio) {
+                spin_unlock_irqrestore(&task->pi_lock, flags);
+                return;
+        }
+
+        /* gets dropped in rt_mutex_adjust_prio_chain()! */
+        get_task_struct(task);
+        spin_unlock_irqrestore(&task->pi_lock, flags);
+
+        rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task __RET_IP__);
+}
+
+/*
  * Slow path lock function:
  */
 static int __sched
@@ -636,6 +665,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
                         if (unlikely(ret))
                                 break;
                 }
+
                 spin_unlock(&lock->wait_lock);
 
                 debug_rt_mutex_print_deadlock(&waiter);
diff --git a/kernel/sched.c b/kernel/sched.c
index 7a30addfd235..2629c1711fd6 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4070,6 +4070,8 @@ recheck:
         __task_rq_unlock(rq);
         spin_unlock_irqrestore(&p->pi_lock, flags);
 
+        rt_mutex_adjust_pi(p);
+
         return 0;
 }
 EXPORT_SYMBOL_GPL(sched_setscheduler);