2.6.25-rc7

 kernel

diff --git a/kernel/rtmutex-debug.c b/kernel/rtmutex-debug.c
index 56d73cb..5fcb4fe 100644
--- a/kernel/rtmutex-debug.c
+++ b/kernel/rtmutex-debug.c
@@ -130,7 +130,7 @@ void debug_rt_mutex_deadlock(int detect, struct rt_mutex_waiter *act_waiter,
 
    task = rt_mutex_owner(act_waiter->lock);
    if (task && task != current) {
-      act_waiter->deadlock_task_pid = task->pid;
+      act_waiter->deadlock_task_pid = get_pid(task_pid(task));
       act_waiter->deadlock_lock = lock;
    }
 }
@@ -142,9 +142,12 @@ void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
    if (!waiter->deadlock_lock || !rt_trace_on)
       return;
 
-   task = find_task_by_pid(waiter->deadlock_task_pid);
-   if (!task)
+   rcu_read_lock();
+   task = pid_task(waiter->deadlock_task_pid, PIDTYPE_PID);
+   if (!task) {
+      rcu_read_unlock();
       return;
+   }
 
    TRACE_OFF_NOLOCK();
 
@@ -173,6 +176,7 @@ void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
       current->comm, task_pid_nr(current));
    dump_stack();
    debug_show_all_locks();
+   rcu_read_unlock();
 
    printk("[ turning off deadlock detection."
           "Please report this trace. ]\n\n");
@@ -203,10 +207,12 @@ void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
    memset(waiter, 0x11, sizeof(*waiter));
    plist_node_init(&waiter->list_entry, MAX_PRIO);
    plist_node_init(&waiter->pi_list_entry, MAX_PRIO);
+   waiter->deadlock_task_pid = NULL;
 }
 
 void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
 {
+   put_pid(waiter->deadlock_task_pid);
    TRACE_WARN_ON(!plist_node_empty(&waiter->list_entry));
    TRACE_WARN_ON(!plist_node_empty(&waiter->pi_list_entry));
    TRACE_WARN_ON(waiter->task);