Re: [PATCH v2] mm/memory-failure: Fix redundant updates for already poisoned pages

[David Hildenbrand <david@redhat.com>]

On 28.08.25 20:38, Kyle Meyer wrote:
> Duplicate memory errors can be reported by multiple sources.
> 
> Passing an already poisoned page to action_result() causes issues:
> 
> * The amount of hardware corrupted memory is incorrectly updated.
> * Per NUMA node MF stats are incorrectly updated.
> * Redundant "already poisoned" messages are printed.
> 
> Avoid those issues by:
> 
> * Skipping hardware corrupted memory updates for already poisoned pages.
> * Skipping per NUMA node MF stats updates for already poisoned pages.
> * Dropping redundant "already poisoned" messages.
> 
> Make MF_MSG_ALREADY_POISONED consistent with other action_page_types and
> make calls to action_result() consistent for already poisoned
> normal pages and huge pages.
> 
> Fixes: b8b9488d50b7 ("mm/memory-failure: improve memory failure action_result messages")
> Signed-off-by: Kyle Meyer <kyle.meyer@hpe.com>
> ---
> 
> v1 -> v2:
>   * Continue passing poisoned pages to action_result() with MF_FAILED but don't
> update anything.
>   * https://lore.kernel.org/all/20250821164445.14467-1-kyle.meyer@hpe.com
> 
> ---
>   mm/memory-failure.c | 13 ++++++-------
>   1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index fc30ca4804bf..10b3c281c2ae 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -956,7 +956,7 @@ static const char * const action_page_types[] = {
>   	[MF_MSG_BUDDY]			= "free buddy page",
>   	[MF_MSG_DAX]			= "dax page",
>   	[MF_MSG_UNSPLIT_THP]		= "unsplit thp",
> -	[MF_MSG_ALREADY_POISONED]	= "already poisoned",
> +	[MF_MSG_ALREADY_POISONED]	= "already poisoned page",
>   	[MF_MSG_UNKNOWN]		= "unknown page",
>   };
>   
> @@ -1349,9 +1349,10 @@ static int action_result(unsigned long pfn, enum mf_action_page_type type,
>   {
>   	trace_memory_failure_event(pfn, type, result);
>   
> -	num_poisoned_pages_inc(pfn);
> -
> -	update_per_node_mf_stats(pfn, result);
> +	if (type != MF_MSG_ALREADY_POISONED) {
> +		num_poisoned_pages_inc(pfn);
> +		update_per_node_mf_stats(pfn, result);
> +	}
>   
>   	pr_err("%#lx: recovery action for %s: %s\n",
>   		pfn, action_page_types[type], action_name[result]);
> @@ -2094,12 +2095,11 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb
>   		*hugetlb = 0;
>   		return 0;
>   	} else if (res == -EHWPOISON) {
> -		pr_err("%#lx: already hardware poisoned\n", pfn);
>   		if (flags & MF_ACTION_REQUIRED) {
>   			folio = page_folio(p);
>   			res = kill_accessing_process(current, folio_pfn(folio), flags);
> -			action_result(pfn, MF_MSG_ALREADY_POISONED, MF_FAILED);
>   		}
> +		action_result(pfn, MF_MSG_ALREADY_POISONED, MF_FAILED);

Was briefly confused by that change, but action_result() now essentially 
only traces + pr_err() with MF_MSG_ALREADY_POISONED.

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Cheers

David / dhildenb