Michal Hocko wrote:
> On Fri 04-08-17 17:25:46, Tetsuo Handa wrote:
> > Well, while lockdep warning is gone, this problem is remaining.
> >
> > diff --git a/mm/memory.c b/mm/memory.c
> > index edabf6f..1e06c29 100644
> > --- a/mm/memory.c
> > +++ b/mm/memory.c
> > @@ -3931,15 +3931,14 @@ int handle_mm_fault(struct vm_area_struct *vma,
> > unsigned long address,
> > /*
> > * This mm has been already reaped by the oom reaper and so the
> > * refault cannot be trusted in general. Anonymous refaults would
> > - * lose data and give a zero page instead e.g. This is especially
> > - * problem for use_mm() because regular tasks will just die and
> > - * the corrupted data will not be visible anywhere while kthread
> > - * will outlive the oom victim and potentially propagate the date
> > - * further.
> > + * lose data and give a zero page instead e.g.
> > */
> > - if (unlikely((current->flags & PF_KTHREAD) && !(ret &
> > VM_FAULT_ERROR)
> > - && test_bit(MMF_UNSTABLE,
> > &vma->vm_mm->flags)))
> > + if (unlikely(!(ret & VM_FAULT_ERROR)
> > + && test_bit(MMF_UNSTABLE, &vma->vm_mm->flags))) {
> > + if (ret & VM_FAULT_RETRY)
> > + down_read(&vma->vm_mm->mmap_sem);
> > ret = VM_FAULT_SIGBUS;
> > + }
> >
> > return ret;
> > }
>
> I have re-read your email again and I guess I misread previously. Are
> you saying that the data corruption happens with the both patches
> applied?
Yes. Data corruption still happens.
