Re: About commit 65fe935d ("x86/KASLR, x86/power: Remove x86 hibernation restrictions")

[Baoquan He]

On 01/25/17 at 05:06pm, Kees Cook wrote:
> On Sun, Jan 22, 2017 at 2:53 AM, Baoquan He <bhe@xxxxxxxxxx> wrote:
> > Hi Kees,
> >
> > In your commit 65fe935dd, you mentioned with the fix of 70595b479ce1,
> > the x86 hibernation restrictions can be removed. However I didn't find
> > it in Linus's tree. I found commit 65c0554 ("x86/power/64: Fix kernel text
> > mapping corruption during image restoration"), it should be the one you
> > mentioned, but not very sure since it was merged later than your commit.
> > Could you help confirm this?
> 
> That sounds correct, yes. There was some last minute additional fixing
> which I think made the referenced commit vanish before Linus merged or
> something like that. 65c0554 looks like the fix it was meaning to
> reference. :)

Thanks for confirming!

> 
> >
> > commit 65fe935dd2387a4faf15314c73f5e6d31ef0217e
> > Author: Kees Cook <keescook@xxxxxxxxxxxx>
> > Date:   Mon Jun 13 15:10:02 2016 -0700
> >
> >     x86/KASLR, x86/power: Remove x86 hibernation restrictions
> >
> >     With the following fix:
> >
> >       70595b479ce1 ("x86/power/64: Fix crash whan the hibernation code passes control to the image kernel")
> >
> >     ... there is no longer a problem with hibernation resuming a
> >     KASLR-booted kernel image, so remove the restriction.
> >
> > commit 65c0554b73c920023cc8998802e508b798113b46
> > Author: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > Date:   Thu Jun 30 18:11:41 2016 +0200
> >
> >     x86/power/64: Fix kernel text mapping corruption during image restoration
> >
> >     Logan Gunthorpe reports that hibernation stopped working reliably for
> >     him after commit ab76f7b4ab23 (x86/mm: Set NX on gap between __ex_table
> >     and rodata).
> >
> > Thanks
> > Baoquan
> 
> 
> 
> -- 
> Kees Cook
> Nexus Security