Don't operate with pid_t in rtmutex tester

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 <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/rtmutex-debug.c b/kernel/rtmutex-debug.c
index 56d73cb8826d86ff75ce0dea818ce658be11cf49..5fcb4fe645e245a4a6c043aedbf1c212dbefadf0 100644 (file)
--- 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 2d3b83593ca3232a0414fc8f808e8435376a9d4c..e124bf5800ea140ceeb936c7cba6429fea0e49b5 100644 (file)
--- 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
 };