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b=QKsjgNPU5/PcGb6udYNlfEODXgk8ivv7ikeYCyFGtk3qXg1WX8QH7JrCzMWxApG6D HRXoVEATmOyWOgmvnMU4f7Jt6iiVHv5eHM/f4tu0MRUlVmtw2VH8m1qwghCR0CTqqW W+iDNL3eGu7Y5patl7mIDeOVyZkN3EEMa5yBpbDAbimNotN9a9qNgkN1TxBWNWn2dT QKi+xC8V8RYoPmWfaroSMUaiEmf7Brtfy5KeymvdgbxHSNMcKtNfnTucAcEjD33pc/ PQdFCVdp+5DKaGCEnlHxsnb+5FwMYO3IfEPaa6Y0EyLznPWk5AnVdC3KqBaaBa6SgV yr5gf3p/wf5/w== Message-ID: <2b7ab53c-b1cc-44f0-acdc-e28967f53ea5@kernel.org> Date: Thu, 20 Nov 2025 14:55:23 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] mm: Use frozen pages for page tables To: Chih-En Lin , "Matthew Wilcox (Oracle)" Cc: Andrew Morton , Vishal Moola , linux-mm@kvack.org References: <20251113140448.1814860-1-willy@infradead.org> <20251113140448.1814860-2-willy@infradead.org> <20251119154654.GA606021@gmail.com> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: <20251119154654.GA606021@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: C2C9B16000B X-Stat-Signature: 5da4tj1gymm7ea5obufkc9636zzcc7ij X-Rspam-User: X-HE-Tag: 1763646927-668388 X-HE-Meta: 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 V5GNpNOo hPDcjnxX7+wXYfAsazovUFEfSyg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: >> +{ >> + struct page *page = ptdesc_page(pt); >> + >> + if (ptdesc_test_kernel(pt)) >> + pagetable_free_kernel(pt); > > Should we use test_and_clear_bit() here to prevent the double free? > Or it is unnecessary because the caller will guarantee there is no other > thread that will free the same pagetables. If that would be the case, it would be horribly broken already? -- Cheers David