Re: [PATCH] Fix resume on x86-32 machines

[Jarkko Nikula]

On 12/11/2017 12:20 AM, Pavel Machek wrote:
> On Sun 2017-12-10 13:58:23, Andy Lutomirski wrote:
> > > On Dec 10, 2017, at 1:38 PM, Pavel Machek <pavel@xxxxxx> wrote:
> > >
> > >
> > > After 4.15-rc2, suspend stopped working on Thinkpad X60. 5b06bbc
> > > (unintentionally?) reordered stuff with respect to
> > > fix_processor_context() on 32-bit and 64-bit. We undo that change on
> > > 32-bit.
> >
> > Can you explain what was wrong with the reordering?  Your patch certainly *looks* incorrect.
>
> No, I can't, sorry.
>
> > I'm guessing that the real issue is that 32-bit needs %fs restored
> >   early for TLS.
>
> Maybe. I can test patches...
>
> I don't think it would be good idea to revert
> 5b06bbcfc2c621da3009da8decb7511500c293ed, but since it introduced
> regression in -rc2, I believe we should fix the regression now, and
> then we can try to provide cleaner solution.
I can confirm Pavel's findings. Commit 5b06bbcfc2c6 ("x86/power: Fix 
some ordering bugs in __restore_processor_context()") broke the 
suspend/resume on 32-bit kernel.

v4.15-rc3 works either by reverting the commit or by Pavel's patch. 
Fortunately Pavel's patch still keeps the 64-bit suspend/resume ok.

--
Jarkko