On Wed, 12 Apr 2023 15:21:38 -0700 Mike Kravetz <mike.kravetz@xxxxxxxxxx> wrote:
> > > Commit a873dfe1032a ("mm, hwpoison: try to recover from copy-on write
> > > faults") introduced the routine copy_user_highpage_mc() to gracefully
> > > handle copying of user pages with uncorrectable errors. Previously,
> > > such copies would result in a kernel crash. hugetlb has separate code
> > > paths for copy-on-write and does not benefit from the changes made in
> > > commit a873dfe1032a.
>
> I was just going to suggest adding the line,
>
> Hence, copy-on-write of hugetlb user pages with uncorrectable errors
> will result in a kernel crash as was the case with 'normal' pages before
> commit a873dfe1032a.
>
> However, I'm guessing it might be more clear if we start with the
> runtime effects. Something like:
>
> copy-on-write of hugetlb user pages with uncorrectable errors will result
> in a kernel crash. This is because the copy is performed in kernel mode
> and in general we can not handle accessing memory with such errors while
> in kernel mode. Commit a873dfe1032a ("mm, hwpoison: try to recover from
> copy-on write faults") introduced the routine copy_user_highpage_mc() to
> gracefully handle copying of user pages with uncorrectable errors. However,
> the separate hugetlb copy-on-write code paths were not modified as part
> of commit a873dfe1032a.
Sounds good. So I assume cc:stable is desirable.
I can't actually get the patch to apply to anything. Can we please
have a redo against current -linus?
