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From: Matthew Wilcox <willy@infradead.org>
To: Ren Wei <enjou1224z@gmail.com>
Cc: linux-mm@kvack.org, pasha.tatashin@soleen.com,
	akpm@linux-foundation.org, vega@nebusec.ai, roxy520tt@gmail.com
Subject: Re: [PATCH 1/1] mm/page_table_check: widen map counters
Date: Sat, 18 Jul 2026 06:17:43 +0100	[thread overview]
Message-ID: <alsMd4aZKfhBE48Z@casper.infradead.org> (raw)
In-Reply-To: <b4414b588418c52a99d959d35a40e064ae8b6e72.1784337674.git.roxy520tt@gmail.com>

On Sat, Jul 18, 2026 at 12:27:20PM +0800, Ren Wei wrote:
> page_table_check_set() and page_table_check_clear() store per-page
> anonymous and file map counts in signed atomic_t counters. A page can
> have more than INT_MAX read-only mappings while still being mapped
> legally.

No it can't.  mapcount is 32-bit.

> The global zero page is one example: repeated read faults on private

You mean "is a special case".  page_table_check should handle this
case specially.



      parent reply	other threads:[~2026-07-18  5:17 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1784337674.git.roxy520tt@gmail.com>
2026-07-18  4:27 ` [PATCH 1/1] mm/page_table_check: widen map counters Ren Wei
2026-07-18  5:11   ` Andrew Morton
2026-07-18  5:31     ` Andrew Morton
2026-07-18 10:21       ` tt roxy
2026-07-19 15:20         ` Pasha Tatashin
2026-07-18  5:17   ` Matthew Wilcox [this message]

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