Messages in this thread | | | Date | Sat, 20 Aug 2022 14:17:02 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v2 1/2] mm/damon: validate if the pmd entry is present before accessing |
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On Thu, 18 Aug 2022 15:37:43 +0800 Baolin Wang <baolin.wang@linux.alibaba.com> wrote:
> The pmd_huge() is used to validate if the pmd entry is mapped by a huge > page, also including the case of non-present (migration or hwpoisoned) > pmd entry on arm64 or x86 architectures. That means the pmd_pfn() can > not get the correct pfn number for the non-present pmd entry, which > will cause damon_get_page() to get an incorrect page struct (also > may be NULL by pfn_to_online_page()) to make the access statistics > incorrect. > > Moreover it does not make sense that we still waste time to get the > page of the non-present entry, just treat it as not-accessed and skip it, > that keeps consistent with non-present pte level entry. > > Thus adding a pmd entry present validation to fix above issues. >
Do we have a Fixes: for this?
What are the user-visible runtime effects of the bug? "make the access statistics incorrect" is rather vague.
Do we feel that a cc:stable is warranted?
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