Re: PI BUG with -rt13

[Ingo Molnar <mingo@elte.hu>]

* david singleton <dsingleton@mvista.com> wrote:

> >both rt_mutex_free() and rt_mutex_set_owner() must be called with the
> >proper locking. David?
> 
>         Yes, the lock  needs to be protected by the robust semaphore.
>         The locking order is:
> 
>                 mmap_sem to protect the vma that holds the pthread_mutex
> 
>                 robust_sem to protect the futex_mutex chain.
> 
>                 futex_mutex - the rt_mutex associated with the 
> pthread_mutex.

well, also lock->wait_lock and lock->pi_lock. The act of making another 
thread the owner of this particular mutex must be performed carefully.  
Check out rt.c to see what locking dependencies there are. (We can also 
do a lockless cmpxchg for unlocked mutexes, under certain 
circumstances.)

	Ingo