-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Ingo Molnar <[EMAIL PROTECTED]>

Testing of -rt by IBM uncovered a locking bug in wake_futex_pi(): the PI
state needs to be locked before we access it.

Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
Acked-by: Thomas Gleixner <[EMAIL PROTECTED]>
Cc: Chuck Ebbert <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>

---
 kernel/futex.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -565,6 +565,7 @@ static int wake_futex_pi(u32 __user *uad
        if (!pi_state)
                return -EINVAL;
 
+       spin_lock(&pi_state->pi_mutex.wait_lock);
        new_owner = rt_mutex_next_owner(&pi_state->pi_mutex);
 
        /*
@@ -604,6 +605,7 @@ static int wake_futex_pi(u32 __user *uad
        pi_state->owner = new_owner;
        spin_unlock_irq(&new_owner->pi_lock);
 
+       spin_unlock(&pi_state->pi_mutex.wait_lock);
        rt_mutex_unlock(&pi_state->pi_mutex);
 
        return 0;

-- 
-
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