Re: [BUG] futex_unlock_pi() hurts my brain and may cause application deadlock

[Steven Rostedt <rostedt@goodmis.org>]

On Wed, 2007-05-30 at 17:49 -0700, john stultz wrote:

> ...
> retry_locked:
> 	/*
> 	 * To avoid races, try to do the TID -> 0 atomic transition
> 	 * again. If it succeeds then we can return without waking
> 	 * anyone else up:
> 	 */
> 	if (!(uval & FUTEX_OWNER_DIED)) {
> 		pagefault_disable();
> 		uval = futex_atomic_cmpxchg_inatomic(uaddr, current->pid, 0);
> 		pagefault_enable();
> 	}

My question is to all the futex gurus out there.

This code is in futex_unlock_pi.  Can the owner of the mutex really die?
Isn't the owner the one doing the unlock?

-- Steve


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