Re: [PATCH -next] mm: hwpoison: support recovery from HugePage copy-on-write faults

[Andrew Morton]

On Tue, 11 Apr 2023 17:27:41 +0800 Liu Shixin <liushixin2@xxxxxxxxxx> wrote:

> Patch a873dfe1032a ("mm, hwpoison: try to recover from copy-on write faults")
> introduced a new copy_user_highpage_mc() function, and fix the kernel crash
> when the kernel is copying a normal page as the result of a copy-on-write
> fault and runs into an uncorrectable error. But it doesn't work for HugeTLB.

What does "doesn't work" mean?  Please fully describe the user-visible
effects of the issue which this patch is addressing.

> This is to support HugeTLB by using copy_mc_user_highpage() in copy_subpage()
> and copy_user_gigantic_page() too.
> 
> Moreover, this is also used by userfaultfd, it will return -EHWPOISON if
> running into an uncorrectable error.