Re: [PATCH v3 3/3] sched, x86: Check that we're on the right stack in schedule and __might_sleep

[Linus Torvalds]

On Mon, May 23, 2016 at 7:09 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>
> What about this silly fix?  (Pardon the probable whitespace damage.)

That looks fine to me, and has a reason for it.

That said, I'm not convinced about the preempt_enable/preempt_disable
excuse: that would be horribly buggy anyway, and has nothing to do
with IST's. Why protect against random insane bugs?

So the "3*" certainly doesn't hurt, but and I won't argue more against
it, but it looks pretty magical and made-up. Might as well just
add/subtract one. You can never protect against people who
intentionally write buggy code, and if it's protecting against
unintentional buggy code I don't see why the IST case is so special
when it's just a tiny fraction of code..

              Linus