Re: [GIT PULL] x86/mm changes for v4.14: PCID support, 5-level paging support, Secure Memory Encryption support

[Ingo Molnar]

* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Mon, Sep 4, 2017 at 2:31 AM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> >
> > Please pull the latest ... git tree from:
> >
> >    git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git ...
> 
> Hmm. My laptop (XPS 13) doesn't resume any more. It suspends, but
> doesn't come back from resume.
> 
> I immediately assumed it was the power management pulls I just did,
> but then I started bisecting, and now it's actually pointing into the
> various x86 pulls I did yesterday instead.
> 
> Now, I'm reasonably early in my bisection (so literally "somewhere
> between the 'docs-next' and the 'x86-mm-for-linus' pull), and maybe
> the problem isn't even entirely repeatable and my bisection has
> already gone off the rails, but I thought I'd give at least an early
> heads-up about this thing.
> 
> I'll have more as it bisects deeper into the merge window, but it
> might be a while.

Hm, just as background, there are no regression reports I'm aware of
against any of these trees, plus most of the dangerous commits have
been in linux-next for at least two weeks - the majority of them even
longer. The last 2-4 commits of x86/mm are fresher.

But it could be a regression in an older commit in x86/mm just as well,
triggered by you for the first time :-/

Does your laptop CPU have PCID support by any chance? The CPU coming
out of resume with PCID disabled and us not properly re-enabling it
might be a possible failure mode.

Thanks,

	Ingo