From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 31CBB3A1A2D; Wed, 14 Jan 2026 21:48:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768427308; cv=none; b=u3Ht+k1ndcXZqlqdXMF5cv0YdmE0ANtTJmdAt9NmjosOz6mWnhzUElSY3SpJguQELWXQPH+ndVUowAEMU7fpGtJAOLLalOSf5vrlbJOlPCBOi1RlpmE+YNPExTdIk2gs5PsS3KJy2YEDTLHgbPMTj4ydqTxG6eXqiPnomoaul3o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768427308; c=relaxed/simple; bh=sVjE+SfQsdIUMHLLdK2WZZMe9meeOIqp+vLdzF39rao=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=LzxoLsEZ3DVYR6AqSMUSlI3YLt5og3DqD4e1eVbXkAVDhgh+R7k4YcQkFT5sNYKu83kjEEXRdDaukea/TijU4UIWBVxJCc/WCHTsN0SG7uIxvfNOpbUsBM94cxGdvT5ehKxfo8koGaUQA2LHfePCK/PhqW0/Vgq+ePAQqmOv4v4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=P6vtWoYC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="P6vtWoYC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 94455C4CEF7; Wed, 14 Jan 2026 21:48:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1768427306; bh=sVjE+SfQsdIUMHLLdK2WZZMe9meeOIqp+vLdzF39rao=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=P6vtWoYCIlr2XYuGHN8Ct1JWv57QVflPPPZ09aqbdSf6sWvv6Psm4BbFl9dEKxvME 9IiuEcpRE83qTyXp72NniYCaihdkRtUtnm5MV6es8ZMUNP2zri1F+QO+WeYttAzUaW ul+FCK9Uuub6AWdHHLL0xvAdQEb3R2ZlrFvcN/18= Date: Wed, 14 Jan 2026 13:48:25 -0800 From: Andrew Morton To: Francois Dugast Cc: intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Matthew Brost , Zi Yan , Alistair Popple , adhavan Srinivasan , Nicholas Piggin , Michael Ellerman , "Christophe Leroy (CS GROUP)" , Felix Kuehling , Alex Deucher , Christian =?UTF-8?B?S8O2bmln?= , David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Lyude Paul , Danilo Krummrich , David Hildenbrand , Oscar Salvador , Jason Gunthorpe , Leon Romanovsky , Lorenzo Stoakes , "Liam R . 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) Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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?