Re: [PATCH][RFC] 4K stacks default, not a debug thing any more...?

Matt Mackall
2007-07-19T01:38:14Z

On Thu, Jul 19, 2007 at 03:33:58AM +0200, Andrea Arcangeli wrote:
> On Thu, Jul 19, 2007 at 01:39:55AM +0100, Alan Cox wrote:
> > > About 4k stacks I was generally against them, much better to fail in
> > > fork than to risk corruption. The per-irq stack part is great feature
> > > instead (too bad it wasn't enabled for the safer 8k stacks).
> >
> > 8K stacks without IRQ stacks are not "safer" so I don't understand your
> > comment ?
>
> Ouch, see the reports about 4k stack crashes. I agree they're not
> safe w/o irq stacks (like on x86-64), but they're generally safer.

Here's a way to make forward progress on this whole thing:

Turn on irqstacks when using 8k stacks
Detect when usage with 8k stacks would overrun a 4k stack when doing
our stack switch and do a WARN_ONCE
Fix up the damn bugs

--
Mathematics is the supreme nostalgia of our time.