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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Balbir Singh , linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, nouveau@lists.freedesktop.org, linux-mm@kvack.org, linux-cxl@vger.kernel.org Subject: Re: [PATCH v5 1/5] mm/zone_device: Reinitialize large zone device private folios Message-Id: <20260114134825.8bf1cb3e897c8e41c73dc8ae@linux-foundation.org> In-Reply-To: <20260114192111.1267147-2-francois.dugast@intel.com> References: <20260114192111.1267147-1-francois.dugast@intel.com> <20260114192111.1267147-2-francois.dugast@intel.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 0F69F1C0010 X-Rspamd-Server: rspam06 X-Stat-Signature: xpqsba8x3y7gkazr6o5kqxra1pq7rkkn X-Rspam-User: X-HE-Tag: 1768427307-148018 X-HE-Meta: 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 +CRZ/m5C BCME76XoXDOVqVhO6flk3Z8tZ/q+SWxgJxpJMBVtT3jTcesPXV3JeQ0j9okqIJg/kvrPc9VBhovG2ZN/FX8SkSYt/5F+14+r+wPxOWa8YWenEgHJc9a+7tZzOI8kOOWZj6bvG1cuCPuOKd5kRp6wPzWOO3bn5Gm54A8vqIZkehXISrrJO0JXCv+n4v5oZjdp5OzzV0i76nZR1RuEo81J9+PSBxm67megWF11xv5blC7G0bTqU18zsqjd2wxBWBTTZ0lF+KFjMNh++brCzo+gALMudI7XZytz6cjYRW3G8N2WEUDYL+2xhziPLSHC/bohttbUj7+5NDfXTRDNAIBRb93360W0+ae70Urc+TrFZqp54eXPLuZbAM/skAQ== 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 Wed, 14 Jan 2026 20:19:52 +0100 Francois Dugast wrote: > Reinitialize metadata for large zone device private folios in > zone_device_page_init prior to creating a higher-order zone device > private folio. This step is necessary when the folio’s order changes > dynamically between zone_device_page_init calls to avoid building a > corrupt folio. As part of the metadata reinitialization, the dev_pagemap > must be passed in from the caller because the pgmap stored in the folio > page may have been overwritten with a compound head. Thanks. What are the worst-case userspace-visible effects of the bug?