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

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Message-ID: <alpine.LRH.2.00.1709062241370.16356@gjva.wvxbf.pm>
Date:   Wed, 6 Sep 2017 22:43:21 +0200 (CEST)
From:   Jiri Kosina <jikos@...nel.org>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
cc:     Ingo Molnar <mingo@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Andy Lutomirski <luto@...nel.org>,
        Borislav Petkov <bp@...en8.de>
Subject: Re: [GIT PULL] x86/mm changes for v4.14: PCID support, 5-level paging
 support, Secure Memory Encryption support

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