Re: [PATCH] mm,hwpoison: unmap poisoned page before invalidation

[Rik van Riel <riel@surriel.com>]

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On Mon, 2022-03-28 at 10:14 +0800, Miaohe Lin wrote:
> On 2022/3/27 4:14, Rik van Riel wrote:
> 
> 
> > 
> > > >                         /* Retry if a clean page was removed
> > > > from
> > > > the cache. */
> > > > -                       if (invalidate_inode_page(vmf->page))
> > > > -                               poisonret = 0;
> > > > -                       unlock_page(vmf->page);
> > > > +                       if (invalidate_inode_page(page))
> > > > +                               poisonret = VM_FAULT_NOPAGE;
> > > > +                       unlock_page(page);
> > 
> 
> Sure, but when I think more about this, it seems this fix isn't
> ideal:
> If VM_FAULT_NOPAGE is returned with page table unset, the process
> will
> re-trigger page fault again and again until invalidate_inode_page
> succeeds
> to evict the inode page. This might hang the process a really long
> time.
> Or am I miss something?
> 
If invalidate_inode_page fails, we will return
VM_FAULT_HWPOISON, and kill the task, instead
of looping indefinitely.

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