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

[Jiri Kosina]

On Tue, 5 Sep 2017, Linus Torvalds wrote:

> > And one of those 18 is commit 10af6235e0d3 ("x86/mm: Implement PCID
> > based optimization: try to preserve old TLB entries using PCID"),
> > which I guess is where the problem might actually start showing up if
> > it is pcid.
> 
> Yup, that's what it bisected down to in the end.
> 
> And then rebooting once more into that kernel, but with "nopcid" on
> the command line, and it all works.
> 
> I'll go back to top-of-tree just to verify that 'nopcid' thing there
> too, but it does seem pretty clear-cut.

This is a "me too", observed on my Lenovo thinkpad x270 (so it's not 
specific to that XPS 13 system at all).

The symptom I observe is that an attempt to resume from hibernation 
proceeds up to reading 100% of the hibernation image, and then reboot 
happens (IOW looks like triple fault).

nopcid cures it, I haven't tried to revert 10af6235e0d3 yet, but looks 
like it's the same thing.

-- 
Jiri Kosina
SUSE Labs