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Date:   Wed, 13 Sep 2023 14:12:04 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Zi Yan <ziy@nvidia.com>
Cc:     Zi Yan <zi.yan@sent.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        David Hildenbrand <david@redhat.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Muchun Song <muchun.song@linux.dev>,
        "Mike Rapoport (IBM)" <rppt@kernel.org>
Subject: Re: [PATCH v3 0/5] Use nth_page() in place of direct struct page
 manipulation
Message-Id: <20230913141204.b32ad42ac917c0e393d82a24@linux-foundation.org>
In-Reply-To: <20230913201248.452081-1-zi.yan@sent.com>
References: <20230913201248.452081-1-zi.yan@sent.com>
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On Wed, 13 Sep 2023 16:12:43 -0400 Zi Yan <zi.yan@sent.com> wrote:

> On SPARSEMEM without VMEMMAP, struct page is not guaranteed to be
> contiguous, since each memory section's memmap might be allocated
> independently. hugetlb pages can go beyond a memory section size, thus
> direct struct page manipulation on hugetlb pages/subpages might give
> wrong struct page. Kernel provides nth_page() to do the manipulation
> properly. Use that whenever code can see hugetlb pages.

for (each patch) {

	Can we please explain why -stable backporting is recommended?

	Such an explanation will, as always, include a description of the
	user-visible effects of the bug.

	Some of the Fixes: targets are very old: 5 years.  Has something
	changed to bring these flaws to light?  Or is it from code inspection?
}

Thanks.