Re: memory offline infinite loop after soft offline

[Michal Hocko]

On Thu 17-10-19 09:34:10, Naoya Horiguchi wrote:
> On Mon, Oct 14, 2019 at 10:39:14AM +0200, Michal Hocko wrote:
[...]
> > diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> > index 89c19c0feadb..5fb3fee16fde 100644
> > --- a/mm/page_isolation.c
> > +++ b/mm/page_isolation.c
> > @@ -274,7 +274,7 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
> >  			 * simple way to verify that as VM_BUG_ON(), though.
> >  			 */
> >  			pfn += 1 << page_order(page);
> > -		else if (skip_hwpoisoned_pages && PageHWPoison(page))
> > +		else if (skip_hwpoisoned_pages && PageHWPoison(compound_head(page)))
> >  			/* A HWPoisoned page cannot be also PageBuddy */
> >  			pfn++;
> >  		else
> 
> This fix looks good to me. The original code only addresses hwpoisoned 4kB-page,
> we seem to have this issue since the following commit,

Thanks a lot for double checking Naoya!
 
>   commit b023f46813cde6e3b8a8c24f432ff9c1fd8e9a64
>   Author: Wen Congyang <wency@xxxxxxxxxxxxxx>
>   Date:   Tue Dec 11 16:00:45 2012 -0800
>   
>       memory-hotplug: skip HWPoisoned page when offlining pages
> 
> and extension of LTP coverage finally discovered this.

Qian, could you give the patch some testing?
---