Re: [PATCH 2/3] x86/mm: Sync also unmappings in vmalloc_sync_one()

[Joerg Roedel]

Hi Thomas,

On Wed, Jul 17, 2019 at 11:43:43PM +0200, Thomas Gleixner wrote:
> On Wed, 17 Jul 2019, Joerg Roedel wrote:
> > +
> > +	if (!pmd_present(*pmd_k))
> > +		return NULL;
> >  	else
> >  		BUG_ON(pmd_pfn(*pmd) != pmd_pfn(*pmd_k));
> 
> So in case of unmap, this updates only the first entry in the pgd_list
> because vmalloc_sync_all() will break out of the iteration over pgd_list
> when NULL is returned from vmalloc_sync_one().
> 
> I'm surely missing something, but how is that supposed to sync _all_ page
> tables on unmap as the changelog claims?

No, you are right, I missed that. It is a bug in this patch, the code
that breaks out of the loop in vmalloc_sync_all() needs to be removed as
well. Will do that in the next version.


Thanks,

	Joerg