[PATCH 4/12] Don't operate with pid_t in rtmutex tester

[Pavel Emelyanov]

The proper behavior to store task's pid and get this task 
later is to get the struct pid pointer and get the task
with the pid_task() call.

Make it for rt_mutex_waiter->deadlock_task_pid field.

Signed-off-by: Pavel Emelyanov <[EMAIL PROTECTED]>

---
 kernel/rtmutex-debug.c  |   12 +++++++++---
 kernel/rtmutex_common.h |    2 +-
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/kernel/rtmutex-debug.c b/kernel/rtmutex-debug.c
index 56d73cb..40ec85c 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);
diff --git a/kernel/rtmutex_common.h b/kernel/rtmutex_common.h
index 2d3b835..e124bf5 100644
--- a/kernel/rtmutex_common.h
+++ b/kernel/rtmutex_common.h
@@ -51,7 +51,7 @@ struct rt_mutex_waiter {
        struct rt_mutex         *lock;
 #ifdef CONFIG_DEBUG_RT_MUTEXES
        unsigned long           ip;
-       pid_t                   deadlock_task_pid;
+       struct pid              *deadlock_task_pid;
        struct rt_mutex         *deadlock_lock;
 #endif
 };
-- 
1.5.3.4

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