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

* Thomas Gleixner <[email protected]> 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 <[email protected]>

	Ingo
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---

• References:
  • [patch 0/4] PI-Futex bugfixes and cleanups
    • From: Thomas Gleixner <[email protected]>
  • [patch 1/4] rt-mutex: Fix stale return value
    • From: Thomas Gleixner <[email protected]>

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