Re: [PATCH v1 1/9] mm/memory: factor out zapping of present pte into zap_present_pte()

[David Hildenbrand]

On 30.01.24 09:13, Ryan Roberts wrote:
> On 29/01/2024 14:32, David Hildenbrand wrote:
> > Let's prepare for further changes by factoring out processing of present
> > PTEs.
> >
> > Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
> > ---
> >   mm/memory.c | 92 ++++++++++++++++++++++++++++++-----------------------
> >   1 file changed, 52 insertions(+), 40 deletions(-)
> >
> > diff --git a/mm/memory.c b/mm/memory.c
> > index b05fd28dbce1..50a6c79c78fc 100644
> > --- a/mm/memory.c
> > +++ b/mm/memory.c
> > @@ -1532,13 +1532,61 @@ zap_install_uffd_wp_if_needed(struct vm_area_struct *vma,
> >   	pte_install_uffd_wp_if_needed(vma, addr, pte, pteval);
> >   }
> >   
> > +static inline void zap_present_pte(struct mmu_gather *tlb,
> > +		struct vm_area_struct *vma, pte_t *pte, pte_t ptent,
> > +		unsigned long addr, struct zap_details *details,
> > +		int *rss, bool *force_flush, bool *force_break)
> > +{
> > +	struct mm_struct *mm = tlb->mm;
> > +	bool delay_rmap = false;
> > +	struct folio *folio;
>
> You need to init this to NULL otherwise its a random value when calling
> should_zap_folio() if vm_normal_page() returns NULL.

Right, and we can stop setting it to NULL in the original function. 
Patch #2 changes these checks, which is why it's only a problem in this 
patch.

Will fix, thanks!

--
Cheers,

David / dhildenb