Re: [patch 1/4] rt-mutex: Fix stale return value

[Ingo Molnar <mingo@elte.hu>]

* Thomas Gleixner <tglx@linutronix.de> wrote:

> -			if (unlikely(!waiter.task))
> +			if (unlikely(!waiter.task)) {
> +				/*
> +				 * Reset the return value. We might
> +				 * have returned with -EDEADLK and the
> +				 * owner released the lock while we
> +				 * were walking the pi chain.
> +				 */
> +				ret = 0;
>  				continue;
> -
> +			}

ok - i guess the reason here that we never triggered it in -rt is that 
-EDEADLK is a really rare case that only occurs with pi-futexes (and 
even then, only with buggy userspace or with intentional testcases). 
Plus, lockdep caught most/all of the in-kernel deadlocks before this 
mechanism could catch it.

Acked-by: Ingo Molnar <mingo@elte.hu>

	Ingo