Re: [PATCH RFC v2 0/2] arm64: vdso: Implement __vdso_futex_robust_try_unlock()

Sebastian Andrzej Siewior
2026-04-28T11:01:11Z

On 2026-04-24 15:55:59 [-0300], André Almeida wrote:
> Hi folks,
Hi,

> This is my take on implementing the new vDSO for unlocking a robust futex in
> arm64. If you don't know what's that, Thomas wrote a good summary,
> including the motivation for this work and the x86 implementation:
>
> https://lore.kernel.org/lkml/878qb89g7b.ffs@tglx/
>
> There are some loose ends in my patchset so I'm sending as a RFC to ask
> some questions:
>
> - If the process is interrupted between the labels, we need to check the
> conditional flags and clear the op_pending address from the register. Using
> objdump I see that op_pending addr is being stored at x2, but I suspect that
> this isn't stable, so I need to figure out how to make sure that the address
> will always be stored in the same register.
> - So far I have implemented only the LL/SC version to make review easier, but I
> can do the LSE version as well.

I am a bit behind here. In the meantime, were you able to check it with
https://lore.kernel.org/all/20260404093939.7XgeW_54@linutronix.de/
?

Sebastian