Re: [TIP][RFC 4/7] futex: finish_futex_lock_pi()

From: Thomas Gleixner
Date: Sat Mar 07 2009 - 10:34:48 EST


On Mon, 2 Mar 2009, Darren Hart wrote:
> + } else {
> + /* dvhart FIXME: can't we just BUG_ON in this case?

No. There is no reason to crash the kernel if this happens. All what
happens is that a userspace application becomes a bit unhappy.

I did not put a WARN_ON there as the stack trace is known, but we
could do a WARN to trigger the kerneloops detector.

> + * Paranoia check. If we did not take the lock in the trylock
> + * above, then we should not be the owner of the rtmutex,
> + * neither the real nor the pending one:
> + */
> + if (rt_mutex_owner(&q->pi_state->pi_mutex) == current)
> + printk(KERN_ERR "finish_futex_lock_pi: "
> + "ret = %d pi-mutex: %p "
> + "pi-state %p\n", ret,
> + q->pi_state->pi_mutex.owner,
> + q->pi_state->owner);
> + }

Thanks,

tglx
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