Re: [PATCH] mm/hwpoison: fix panic due to split huge zero page

[Wanpeng Li]

On 8/12/15 5:14 AM, Andrew Morton wrote:
> On Tue, 11 Aug 2015 18:47:57 +0800 Wanpeng Li <wanpeng.li@xxxxxxxxxxx> wrote:
>
> > ...
> >
> > Huge zero page is allocated if page fault w/o FAULT_FLAG_WRITE flag.
> > The get_user_pages_fast() which called in madvise_hwpoison() will get
> > huge zero page if the page is not allocated before. Huge zero page is
> > a tranparent huge page, however, it is not an anonymous page. memory_failure
> > will split the huge zero page and trigger BUG_ON(is_huge_zero_page(page));
> > After commit (98ed2b0: mm/memory-failure: give up error handling for
> > non-tail-refcounted thp), memory_failure will not catch non anon thp
> > from madvise_hwpoison path and this bug occur.
> So I'm assuming this patch is needed for 4.2 but not in earlier
> kernels.

I think so. :-)  Btw, how about my other hwpoison patches?

Regards,
Wanpeng Li

>

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