Re: [PATCH v5] mm: Fix a hmm_range_fault() livelock / starvation problem

[Alistair Popple]

On 2026-02-12 at 09:23 +1100, Davidlohr Bueso <d...@stgolabs.net> wrote...
> On Tue, 10 Feb 2026, Thomas Hellstr�m wrote:
> 
> > @@ -176,7 +176,7 @@ static int migrate_vma_collect_huge_pmd(pmd_t *pmdp, 
> > unsigned long start,
> >             }
> > 
> >             if (softleaf_is_migration(entry)) {
> > -                   migration_entry_wait_on_locked(entry, ptl);
> > +                   softleaf_entry_wait_on_locked(entry, ptl);
> >                     spin_unlock(ptl);
> 
> softleaf_entry_wait_on_locked() unconditionally drops the ptl.

As does migration_entry_wait_on_locked() so obviously a pre-existing issue.
I'm not sure why we would wait on a migration entry here though, maybe Balbir
can help?

> >                     return -EAGAIN;
> >             }