Re: [BUG -tip] kmemleak and stacktrace cause page faul

From: Cyrill Gorcunov
Date: Wed Oct 23 2019 - 09:44:19 EST


On Wed, Oct 23, 2019 at 03:38:40PM +0200, Thomas Gleixner wrote:
> > >
> > > [0,2,4,5,6,8,10,12] are guard pages so 0 is not that crappy at all
> >
> > Wait, Thomas, I might be wrong, but per-cpu is initialized to the pointer,
> > the memory for this estack_pages has not yet been allocated, no?
>
> static const
> struct estack_pages estack_pages[CEA_ESTACK_PAGES] ____cacheline_aligned = {
> EPAGERANGE(DF),
> EPAGERANGE(NMI),
> EPAGERANGE(DB1),
> EPAGERANGE(DB),
> EPAGERANGE(MCE),
> };
>
> It's statically allocated. So it's available from the very beginning.

Indeed, thanks! I happened to overlooked this moment.
...
> And as I explained to you properly decoded the values _ARE_ correct and
> make sense.

Yes, just posted the diff itself to be sure. Thanks a huge for
explanation, Thomas!