Re: [PATCH 1/2] KVM: MMU: fix SMAP virtualization

From: Andrew Morton
Date: Wed Jun 10 2015 - 14:09:01 EST


On Wed, 10 Jun 2015 11:02:46 -0700 Davidlohr Bueso <dave@xxxxxxxxxxxx> wrote:

> On Wed, 2015-05-27 at 10:53 +0800, Xiao Guangrong wrote:
> >
> > On 05/26/2015 10:48 PM, Paolo Bonzini wrote:
> > >
> > >
> > > On 26/05/2015 16:45, Edward Cree wrote:
> > >>>> This breaks older compilers that can't initialize anon structures.
> > >>>>
> > >>>> How old ? Even gcc 3.1 says you can use unnamed struct/union fields and
> > >>>> 3.2 is the minimum version required to compile the kernel as mentioned
> > >>>> in the README.
> > >>>>
> > >>>> We could simply just name the structure, but I doubt this is the
> > >>>> only place in the kernel code where it's being used this way :)
> > >> This appears to be GCC bug #10676, see <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=10676>
> > >> Says it was fixed in 4.6, but I believe the kernel supports GCCs much older
> > >> than that (back to 3.2). I personally hit it on 4.4.7, the version shipped
> > >> with RHEL6.6.
> > >
> > > Yes, it will be fixed soon(ish). Probably before you can get rid of the
> > > obnoxious disclaimer... :)
> >
> > It has been fixed by Andrew:
> >
> > From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > Subject: arch/x86/kvm/mmu.c: work around gcc-4.4.4 bug
>
> Folks, this fix is missing in both -tip and Linus' (4.1-rc7) tree. At
> least I'm running into it.

hm, yes, it's in linux-next so I dropped my copy.

I'll send it in to Linus today.
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