NPTL futex error handling

[Siddhesh Poyarekar]

On 27 January 2014 19:57, Florian Weimer <fweimer@redhat.com> wrote:
> Looking at the kernel code, I believe that FUTEX_LOCK_PI and FUTEX_WAKE (in
> the case of cross-process mutexes, it seems) can fail with ENOMEM, in
> addition to the more-or-less expected failure cases.
>
> Is the ENOMEM return value due to kernel changes after the initial futex
> implementation, or has this already been evaluated and deemed not be
> necessary for correctness?

I guess you're referring to the return from refill_pi_state_cache?
The allocation happens only once, so the chances of it failing are
very remote.  One could engineer a failure I guess, by exhausting
memory before the first call to pthread_mutex_lock on a PI mutex.  I'm
not sure how useful that would be, but it might be worth a look.

Siddhesh
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