Re: [PATCH 4.0 00/58] 4.0.9-stable review

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, Jul 21, 2015 at 05:02:31PM -0400, Donald Parsons wrote:
> On Tue, 2015-07-21 at 11:13 -0700, Greg Kroah-Hartman wrote:
> > On Tue, Jul 21, 2015 at 01:13:27PM -0400, Donald Parsons wrote:
> > > Greg,
> > > 
> > > The kernel still does not compile with gcc-4.5.1 since linux-4.0.5 when
> > > a kvm back-port from 4.1-rc5 went in.  (This is on Linux 4.1.2 SMP Mon
> > > Jul 13 18:08:30 EDT 2015 x86_64      Fedora 14)
> > > 
> > > This mis-compile was fixed in 4.1-rc8.  The diff was:
> > > 
> > > diff -ur linux-4.1-rc7/arch/x86/kvm/mmu.c
> > > linux-4.1-rc8/arch/x86/kvm/mmu.c
> > > --- linux-4.1-rc7/arch/x86/kvm/mmu.c	2015-07-15 00:05:34.000000000 -0400
> > > +++ linux-4.1-rc8/arch/x86/kvm/mmu.c	2015-07-15 00:07:45.000000000 -0400
> > > @@ -4215,13 +4215,13 @@
> > >  	u64 entry, gentry, *spte;
> > >  	int npte;
> > >  	bool remote_flush, local_flush, zap_page;
> > > -	union kvm_mmu_page_role mask = (union kvm_mmu_page_role) {
> > > -		.cr0_wp = 1,
> > > -		.cr4_pae = 1,
> > > -		.nxe = 1,
> > > -		.smep_andnot_wp = 1,
> > > -		.smap_andnot_wp = 1,
> > > -	};
> > > +	union kvm_mmu_page_role mask = { };
> > > +
> > > +	mask.cr0_wp = 1;
> > > +	mask.cr4_pae = 1;
> > > +	mask.nxe = 1;
> > > +	mask.smep_andnot_wp = 1;
> > > +	mask.smap_andnot_wp = 1;
> > >  
> > >  	/*
> > >  	 * If we don't have indirect shadow pages, it means no page is
> > > 
> > > 
> > > Please add to linux-4.0.9 so older compilers will work.
> > 
> > What is the commit id in Linus's tree that resolves this?
> 
> I do not know but I found this in Linus' linux-4.1-rc8 email announce:
> 
> Andrew Morton (1):
>       arch/x86/kvm/mmu.c: work around gcc-4.4.4 bug
> 
> which must be it.  Added Andrew to cc as he hopefully knows the answer
> to your question.

You can dig through git to find it pretty easily...

Anyway, given that the 4.0 release I'm doing at the moment is the last
one, and it's end-of-life, this is a bit late and isn't going to matter
much.  People should be on 4.1 already.

thanks,

greg k-h