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From: Muchun Song <muchun.song@linux.dev>
To: Oscar Salvador <osalvador@suse.de>
Cc: Ge Yang <yangge1116@126.com>,
	akpm@linux-foundation.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	21cnbao@gmail.com, david@redhat.com,
	baolin.wang@linux.alibaba.com, liuzixing@hygon.cn
Subject: Re: [PATCH] mm/hugetlb: fix kernel NULL pointer dereference when replacing free hugetlb folios
Date: Thu, 22 May 2025 20:39:39 +0800	[thread overview]
Message-ID: <3B8641A1-5345-44A5-B610-9BCBC980493D@linux.dev> (raw)
In-Reply-To: <aC8PRkyd3y74Ph5R@localhost.localdomain>



> On May 22, 2025, at 19:49, Oscar Salvador <osalvador@suse.de> wrote:
> 
> On Thu, May 22, 2025 at 07:34:56PM +0800, Ge Yang wrote:
>> It seems that we cannot simply remove the folio_test_hugetlb() check. The
>> reasons are as follows:
> 
> Yeah, my thought was whether we could move the folio_hstate within
> alloc_and_dissolve_hugetlb_folio(), since the latter really needs to take the
> lock.
> But isolate_or_dissolve_huge_page() also needs the 'hstate' not only to
> pass it onto alloc_and_dissolve_hugetlb_folio() but to check whether
> hstate is gigantic.

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.

> 
> Umh, kinda hate sparkling the locks all around.
> 
> 
> -- 
> Oscar Salvador
> SUSE Labs



  reply	other threads:[~2025-05-22 12:40 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-22  3:22 yangge1116
2025-05-22  3:47 ` Muchun Song
2025-05-22  5:34   ` Oscar Salvador
2025-05-22  7:13     ` Muchun Song
2025-05-22 10:13       ` Oscar Salvador
2025-05-22 11:34     ` Ge Yang
2025-05-22 11:49       ` Oscar Salvador
2025-05-22 12:39         ` Muchun Song [this message]
2025-05-22 19:32           ` Oscar Salvador
2025-05-23  3:27             ` Muchun Song
2025-05-23  3:46               ` Ge Yang
2025-05-23  3:56                 ` Muchun Song
2025-05-23  5:30                 ` Oscar Salvador
2025-05-23  8:07                   ` Ge Yang
2025-05-22 11:50 ` Oscar Salvador
2025-05-26 12:41 ` David Hildenbrand
2025-05-26 12:57   ` Ge Yang
2025-05-26 12:59     ` David Hildenbrand

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