Re: [PATCH stable/linux-6.6.y] mm/memory-failure: fix missing ->mf_stats count when hugetlb folio already poisoned

[Qi Xi <xiqi2@huawei.com>]

On 21/07/2026 21:06, Greg Kroah-Hartman wrote:
> On Tue, Jul 14, 2026 at 09:45:03AM +0800, Qi Xi wrote:
>> Add stable@ to Cc.
>>
>> On 06/07/2026 16:41, Qi Xi wrote:
>>> When a new subpage is poisoned on a hugetlb folio that has already been
>>> marked hwpoison (MF_HUGETLB_FOLIO_PRE_POISONED), hugetlb_update_hwpoison()
>>> increments num_poisoned_pages directly, but the per-node ->mf_stats is
>>> not updated because this path bypasses action_result(). This leaves the
>>> two accounting counters inconsistent within the hardware memory-failure
>>> path: a new poison event is counted in num_poisoned_pages but not reflected
>>> in the per-node mf_stats.
>>>
>>> In mainline, commit a148a2040191 ("mm/memory-failure: fix missing
>>> ->mf_stats count in hugetlb poison") fixed this by removing the direct
>>> num_poisoned_pages_inc() from the helper and adding action_result() calls
>>> in try_memory_failure_hugetlb() for the already-poisoned cases. The
>>> backport to linux-6.6.y as commit 252bb328b36f ("mm/memory-failure: fix
>>> missing ->mf_stats count in hugetlb poison") applied the refactoring
>>> (naming, constants, switch-case) but omitted the core counting fix,
>>> leaving the inconsistency in place.
>>>
>>> Fix this by adding a matching update_per_node_mf_stats() call alongside
>>> the existing num_poisoned_pages_inc() in the same block, so both counters
>>> stay consistent without restructuring the error path.
>>>
>>> Fixes: 252bb328b36f ("mm/memory-failure: fix missing ->mf_stats count in hugetlb poison")
>>> Signed-off-by: Qi Xi <xiqi2@huawei.com>
> We need acks/reviews by the relevant maintainers before we can accept
> something like this.

Thank you for the feedback. I have resent this patch to
stable@vger.kernel.org with the correct format (including upstream
commit reference and proper stable submission format):

https://lore.kernel.org/stable/20260721121956.124887-1-xiqi2@huawei.com/

I'll also work on getting the required Reviewed-by/Acked-by from
the mm/memory-failure maintainers.

Qi

>
> thanks,
>
> greg k-h
>