From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 6B3083438A8 for ; Thu, 17 Sep 2026 16:03:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660999; cv=none; b=QQh+PeB3s5kmTzd1NWjAPMq8XRgIexuDU8kduoqrac+AzGBEU5MQa/hR0Wz4Cl8zz3zDbZLeP0sHiapc7CIA9lgZfzfCLPR3iFvUXlOGqHH3ejLRkhh7q8UKh9DC/g2aQu/aeqZFOQBvmhPlNF9/USHi5gfLuFeDAI2rGLEnMBI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660999; c=relaxed/simple; bh=bji6kgyW1R2VmlJjfjX09W0brxlZ3p+S+hs/OMlhbR8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=B9GuW0o8OWcxub4coMza/LRfUUtMDFX5TnBaBv6Bo8GCcRs0BnAQnhvmhu0/L5F+KBZb5n69InOxH3J1iv0Ri4j/A5nJ4MCJcdMaO08XwmbrBpDDjq8Z/um99+U499pfeYsHT+00RnJMRx6ZVg8HYARaQ9AEJ3gKju76BS8QegQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iCyqXecE; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iCyqXecE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0465F1F00899; Thu, 17 Sep 2026 16:03:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789660996; bh=Cpr1q5iPo4prGN6gHLTCnzlEG3QCR+sTiAllOyw0NCg=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=iCyqXecEXXVSPfVycrbJM29G7wUwtFS1xEC3VTKCCCVZ3pVzhWC5rFCf7i9ypiYuV 4NbkfjBZU1n8h+bdQHCSNHej39CBcy9jO8lMDQyZ9nTfxIkMyZQx1S0Jj8Ubuw4THn RumPVt6hJdZlyBCfIG2tRzCeMxjYplAj7TNbIXoSc45GKUPJsvsaPbAkEIRQVbgyvn lvYRoZgVwXLd9ggl0AlTcO8nQCBmGI310S4T8kaCyc5d2d0S6R++DhqLrLFHl+wrvg 0SnHpjMefPK6bEnEbVWjhOvB20WRinGUdZa1elsmCc78b587xzVWf2iyrzZX+V9BnX i9eTyO3XMMd0Q== Received: from phl-compute-05.internal (phl-compute-05.internal [10.202.2.45]) by mailfauth.ams.internal (Postfix) with ESMTP id 79507198003A; Thu, 17 Sep 2026 12:03:11 -0400 (EDT) Received: from phl-frontend-04 ([10.202.2.163]) by phl-compute-05.internal (MEProxy); Thu, 17 Sep 2026 12:03:13 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: dmFkZTFnWkP/oAjipqhpTyrH15eGRA2bD+A1Xse0B1GSy4xsn8XucvU9sl01MM0Ad0L70K RV8rNBOACHl/J1H6Nd7+ghCe17B4OtPsza4h/afczVaboD6XRqg2guprqOWvlU/5CndUAg sQ6kUD57YdyJu/WvN0rt/M5l5nKVGS591lpJ/WU2LBIWGf7Vp6j+m5x98KMIj2AD66Tsjw KWbEf23UJsl1IsBoDBtObZNzY/nesLje/i595bUpiDidS6up0Icxc7FOr2hpXeOxO6Jrul EhWqE8wLo1kUgPbR7ABGGoWKKCdzS3x+CNyoU4etePtnXw8nYT+SRbEW9s8SpefM/Vconi E/N6yZH/A04TnMVgCjMdA1NuwXfBgqBFW2TpWi2bm6r643LmRbAHWO0Zx8bdtplEuPGQSQ EOZc2tyGZtU8z9wgpFhPqBSx7J+CEdwfkBHoGpkZ3rdh5nwD+zBEelJEkoc0Yie39JVFjb Na98vLAMsiOUHwPQUGEcM9bButD8GnTmzzCYGVQDVIYQMOGWS/hbwZj+WMe0wlaeeaQgDN rEHmbHAWKWKL9gXUV0Evous+WVXD8DN3NPJwJ9fV77QPCfN6ftjx/c4ia9EUdmqsedZUI2 sDbBalUG3HP9Ee4TCZKbMDvgTArPeS7pkSYvcoodvihft81sk6egcXWFKwpg X-ME-Proxy: Feedback-ID: i10464835:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Thu, 17 Sep 2026 12:03:10 -0400 (EDT) Date: Thu, 17 Sep 2026 17:03:09 +0100 From: Kiryl Shutsemau To: "David Hildenbrand (Arm)" Cc: Lance Yang , akpm@linux-foundation.org, ziy@nvidia.com, baolin.wang@linux.alibaba.com, liam@infradead.org, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, usama.arif@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] mm/huge_memory: disallow raw PMD mappings of the huge zero page Message-ID: References: <20260917121010.60966-1-lance.yang@linux.dev> <8c70259a-94ed-415c-89c1-572145c64670@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8c70259a-94ed-415c-89c1-572145c64670@kernel.org> On Thu, Sep 17, 2026 at 05:29:48PM +0200, David Hildenbrand (Arm) wrote: > On 9/17/26 16:32, Kiryl Shutsemau wrote: > > On Thu, Sep 17, 2026 at 08:10:10PM +0800, Lance Yang wrote: > >> vm_mixed_zeropage_allowed() validates zeropage insertion into > >> VM_MIXEDMAP VMAs. No in-tree user needs to insert the huge zero page > >> through vmf_insert_pfn_pmd(). > >> > >> Return VM_FAULT_SIGBUS if vmf_insert_pfn_pmd() is asked to map it. > >> > >> Link: https://lore.kernel.org/linux-mm/f76beaf8-351a-4b22-b362-a945a5e1af6a@kernel.org/ > >> Suggested-by: Kiryl Shutsemau > >> Suggested-by: David Hildenbrand > >> Signed-off-by: Lance Yang > > > > The patch looks fine, but don't we want to cover the same for non-huge > > zero page in vmf_insert_pfn_prot()? > > Why would the zeropage be a problem in PFNMAP mapping? Nothing enforces that it is read-only. -- Kiryl Shutsemau / Kirill A. Shutemov