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Shutemov" , Yang Shi , David Hildenbrand , Jiaqi Yan , linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 3/3] mm/khugepaged: maintain page cache uptodate flag Message-ID: References: <20230307052036.1520708-1-stevensd@google.com> <20230307052036.1520708-4-stevensd@google.com> <866d1a75-d462-563-dfd7-1aa2971a285b@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <866d1a75-d462-563-dfd7-1aa2971a285b@google.com> X-Rspam-User: X-Rspamd-Queue-Id: 4A56BC0007 X-Rspamd-Server: rspam01 X-Stat-Signature: izt4yjydhcqt3jqemzw7wgoxfsbc6ffa X-HE-Tag: 1679608576-387691 X-HE-Meta: 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 RywMjbQM KuoGHxz7p5fOtfgmXfcjHm3EHh7u3Sv0eggdBj9Ni8OWAonGzlhUoxk0UJOvcQq9UWwfAPGs4NwL3llqv3zkWfbaPI9og83dnZZ+c9DvKPD4ZZQpw0h0j+9jovD+a1TzBPtQtC+WZTq5Nelz3KA16j3yMTodl/K5okjBXl8zEvG29S0LwGSk0xPW4yA== 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: On Thu, Mar 23, 2023 at 12:07:46PM -0700, Hugh Dickins wrote: > On an earlier audit, for different reasons, I did also run across > lib/buildid.c build_id_parse() using find_get_page() without checking > PageUptodate() - looks as if it might do the wrong thing if it races > with khugepaged collapsing text to huge, and should probably have a > similar fix. That shouldn't be using find_get_page(). It should probably use read_cache_folio() which will actually read in the data if it's not present in the page cache, and return an ERR_PTR if the data couldn't be read.