Re: [PATCH] mm/memory-failure: fix hardware poison check in unpoison_memory()

[Jane Chu]

On 7/17/2023 11:18 AM, Sidhartha Kumar wrote:
> It was pointed out[1] that using folio_test_hwpoison() is wrong
> as we need to check the indiviual page that has poison.
> folio_test_hwpoison() only checks the head page so go back to using
> PageHWPoison().
>
> Reported-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> Fixes: a6fddef49eef ("mm/memory-failure: convert unpoison_memory() to folios")
> Cc: stable@xxxxxxxxxxxxxxx #v6.4
> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
>
> [1]: https://lore.kernel.org/lkml/ZLIbZygG7LqSI9xe@xxxxxxxxxxxxxxxxxxxx/
> ---
>   mm/memory-failure.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 02b1d8f104d51..a114c8c3039cd 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -2523,7 +2523,7 @@ int unpoison_memory(unsigned long pfn)
>   		goto unlock_mutex;
>   	}
>   
> -	if (!folio_test_hwpoison(folio)) {
> +	if (!PageHWPoison(p)) {
>   		unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n",
>   				 pfn, &unpoison_rs);
>   		goto unlock_mutex;

Would it worth the trouble to create folio_page_test_##lname(folio, 
index) macros to address folio subpage?

thanks!
-jane