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b=PaeJ5RittgcFyauGs4iFTI03D8aARwFnljv02mb/OI32cyBI880Z0Ao7pV1jeABQD qPJaD63vKD/fQ30QyRvb9cIgbK+IKhGUOd0OAq1rT4luW3hdj+DJpKIEbOBsLumYug 2h/alC4i+oy8qxiZoguwXiJZL82N8Ac2i9ERsPk3wlncH01qZjgWXY2l6Cnuw5hBwH nQbj/jZCWMmiiMt7aw44/RyA60jSugr/IJsjhVnJ5MnVJNDmaJj/AfeN1w86NttJqm FRnKfSt/5eF6xGW5FWxFoyEbnEshogxwgeZKSNjcEE+mTk0pHdYV5PQVpTZyjAHtSv z1qVL+7jaNHQQ== From: Pratyush Yadav To: Pratyush Yadav Cc: Michal Clapinski , Evangelos Petrongonas , Pasha Tatashin , Mike Rapoport , Alexander Graf , kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton Subject: Re: [PATCH v2] kho: add support for deferred struct page init In-Reply-To: <2vxzecmssnxx.fsf@kernel.org> (Pratyush Yadav's message of "Tue, 10 Feb 2026 14:55:22 +0100") References: <20260210130418.297153-1-mclapinski@google.com> <2vxzecmssnxx.fsf@kernel.org> Date: Tue, 10 Feb 2026 15:00:22 +0100 Message-ID: <2vxza4xgsnpl.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspam-User: X-Rspamd-Queue-Id: 1DD20C0014 X-Rspamd-Server: rspam07 X-Stat-Signature: cnb1bqduxmw37y3ch3ajkjiwbbe8phgm X-HE-Tag: 1770732026-718979 X-HE-Meta: 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 PMJ7TiWF SSgh/DudKRXHJ0oMOp8UllAwdY23Gow6lnnv57GFHvzfCSXfMmPLTffEEtmEYwi+nbs6ctubKjQA+nAz26/iZNhD3I0Hs4EJN5Ov73LqXWIyBTiAc69jCVPyJmUm7HplMlvugeJn8dH19vYXwqNPH2u85rPZJl+HEmGHUcddJt2Ohtv4mxIWbIVznD0ic+LYDQXBPSKv7pMEoLV5cUttX/ZDx+Q== 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: On Tue, Feb 10 2026, Pratyush Yadav wrote: > On Tue, Feb 10 2026, Michal Clapinski wrote: > >> When `CONFIG_DEFERRED_STRUCT_PAGE_INIT` is enabled, struct page >> initialization is deferred to parallel kthreads that run later >> in the boot process. >> >> During KHO restoration, `deserialize_bitmap()` writes metadata for >> each preserved memory region. However, if the struct page has not been >> initialized, this write targets uninitialized memory, potentially >> leading to errors like: >> ``` >> BUG: unable to handle page fault for address: ... >> ``` >> >> Fix this by introducing `kho_get_preserved_page()`, which ensures >> all struct pages in a preserved region are initialized by calling >> `init_deferred_page()` which is a no-op when deferred init is disabled >> or when the struct page is already initialized. >> >> Signed-off-by: Evangelos Petrongonas >> Signed-off-by: Michal Clapinski > > Reviewed-by: Pratyush Yadav (Google) Wait. I just noticed that Michal took authorship of the patch. I talked to him and he said that was by mistake. Andrew, can you please give the authorship to Evangelos when you queue the patch? -- Regards, Pratyush Yadav