Re: [RFC v2 PATCH] futex: extend set_robust_list to allow 2 locking ABIs at the same time.

[Zack Weinberg]

On Tue, Nov 5, 2019 at 9:28 AM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> The real issue is that the robust list could be circular by incident or
> malice and there is no way for the kernel to figure that out. That would
> prevent the task from exiting and make it iterate over the list until
> doomsday, i.e. a nice unpriviledged DoS.

Why can't the kernel use the standard tortoise-and-hare algorithm for
detecting circular linked lists here?

zw