Re: [PATCH] mm/hugetlb: fix kernel NULL pointer dereference when replacing free hugetlb folios

[Muchun Song <muchun.song@linux.dev>]

> On May 23, 2025, at 11:46, Ge Yang <yangge1116@126.com> wrote:
> 
> 
> 
> 在 2025/5/23 11:27, Muchun Song 写道:
>>> On May 23, 2025, at 03:32, Oscar Salvador <osalvador@suse.de> wrote:
>>> 
>>> On Thu, May 22, 2025 at 08:39:39PM +0800, Muchun Song wrote:
>>>> But I think we could use "folio_order() > MAX_PAGE_ORDER" to replace the check
>>>> of hstate_is_gigantic(), right? Then ee could remove the first parameter of hstate
>>>> from alloc_and_dissolve_hugetlb_folio() and obtain hstate in it.
>>> 
>>> Yes, I think we can do that.
>>> So something like the following (compily-tested only) maybe?
>>> 
>>> From d7199339e905f83b54d22849e8f21f631916ce94 Mon Sep 17 00:00:00 2001
>>> From: Oscar Salvador <osalvador@suse.de>
>>> Date: Thu, 22 May 2025 19:51:04 +0200
>>> Subject: [PATCH] TMP
>>> 
>>> ---
>>>  mm/hugetlb.c | 38 +++++++++-----------------------------
>>>  1 file changed, 9 insertions(+), 29 deletions(-)
>> Pretty simple. The code LGTM.
>> Thanks.
> 
> Thanks.
> 
> The implementation of alloc_and_dissolve_hugetlb_folio differs between kernel 6.6 and kernel 6.15. To facilitate backporting, I'm planning to submit another patch based on Oscar Salvador's suggestion.

A separate improving patch LGTM.

>