Re: [RFC PATCH] x86/mm/fault: Allow stack access below %rsp

[Andy Lutomirski]

On Fri, Nov 2, 2018 at 12:50 PM Waiman Long <longman@xxxxxxxxxx> wrote:
>
> On 11/02/2018 03:44 PM, Dave Hansen wrote:
> > On 11/2/18 12:40 PM, Waiman Long wrote:
> >> The 64k+ limit check is kind of arbitrary. So the check is now removed
> >> to just let expand_stack() decide if a segmentation fault should happen.
> > With the 64k check removed, what's the next limit that we bump into?  Is
> > it just the stack_guard_gap space above the next-lowest VMA?
>
> I think it is both the stack_guard_gap space above the next lowest VMA
> and the rlimit(RLIMIT_STACK).
>

Did the non-working programs ever work?  Because, if not, I say let them fail.