Re: fs/exec.c: use BUILD_BUG_ON for VM_STACK_FLAGS &VM_STACK_INCOMPLETE_SETUP

[Michal Hocko]

On Wed 15-06-11 21:52:07, Andrew Morton wrote:
> On Wed, 15 Jun 2011 21:45:00 -0700 Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> 
> > On Wed, Jun 15, 2011 at 9:35 PM, Randy Dunlap <randy.dunlap@xxxxxxxxxx> wrote:
> > >
> > > fwiw, I just reported that this causes a build error in UML on x86_64
> > > in mmotm-2011-06-15:
> > 
> > Gaah. That sounds really familiar. Have we done this same mistake once
> > before already, or is it just deja-vu for some other reason.
> > 
> > On x86-64 UML, we have
> > 
> >   #define VM_STACK_DEFAULT_FLAGS vm_stack_flags
> > 
> > so VM_STACK_FLAGS ends up not being a constant, even though it really
> > looks like one.
> > 
> > UML is _really_ confused in this area, btw. It seems to re-define that
> > thing if TIF_IA32 is defined. That's some crazy stuff. Doesn't the
> > compiler warn about it?
> > 
> > I guess I should just revert that commit, though. Even if it does seem
> > to be the case that UML is just being crazy. Andrew?
> > 
> 
> Sure, it was just a tiny optimization.

Please revert and sorry for this.

-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic
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