Re: [patch 1/2] x86/mm/pti: Handle unaligned address gracefully in pti_clone_pagetable()

[Thomas Gleixner]

On Wed, 28 Aug 2019, Ingo Molnar wrote:
> >  		pmd = pmd_offset(pud, addr);
> >  		if (pmd_none(*pmd)) {
> > -			addr += PMD_SIZE;
> > +			WARN_ON_ONCE(addr & PMD_MASK);
> > +			addr = round_up(addr + 1, PMD_SIZE);
> 
> So given that PUD_MASK and PMD_MASK are masking out the *offset*:
> 
>  arch/x86/include/asm/pgtable_64_types.h:#define PMD_MASK	(~(PMD_SIZE - 1))
> 
> Didn't we want something like:
> 
> 			WARN_ON_ONCE(addr & ~PUD_MASK);
> 
> 			WARN_ON_ONCE(addr & ~PMD_MASK);
> 
> to warn about an unaligned 'addr', or am I misreading the intent here?

Bah, right you are...