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 58D574E3769 for ; Thu, 17 Sep 2026 15:29:54 +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=1789659005; cv=none; b=dWjH81xEZsFf9be/n3qaUICQvF7HiNiJsuVny8P8b/Uhk/HTi48sJCwuQw7xPgtKYSYhnmiI5arSOqDquGU6IpPkEaAxxc+/Cr+j9HT6leKFH/CEqKjptl452E0IKW5UznhgSd/kzQx95Vp/75rG88LQCrMIW4a4laIztfZNl2w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789659005; c=relaxed/simple; bh=7A/Tag6UaadTOgPEEgnC+Vz/ftb96urxScJUivK0TRI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=NMy39EKT5sUazYszM/pwZTWZZqed6/mMd5D4liSbMqeQzd426HDbD/748ZvGw8Un+2i7pVdPI1Zh1uSmIcUSYPuxbaFmlYQ2P7YQTznL6bUWUpfXvwp1OW4PqaTaGHigPImB36GxrkOQA3C8Y7R/c8foqRuS9tjxAhFPnFh/dUU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fxgCSlx5; 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="fxgCSlx5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D90921F0089A; Thu, 17 Sep 2026 15:29:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789658993; bh=/WxPtrIuAEb4+1h/R5tbokixOnDPh0mmusu48M2O2g4=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=fxgCSlx51Fk9w6LKE73pPGRFcbVnACo3pctojXHqHqz3aUqccWa1r7ZW7mbkZ/vrp RrqubvT3M7YmFzgQgaSQOOfzcxNsOWyW85r4GkrpdUfJOO+nWj5jxJhR/SZRYvzrW3 ffiSBfA7WOyg5BtEDQJ2HAlzcFtfr0s+W/H0uPgqFl9nNVw5jhnoEX7KMTa6AYXkp5 4u9pap0dbIVXzJE9wAIWn+ZEyW0f1Nf+LmylfWX/wU6GwnUY2edAOfTF+szxCgdanI Xk5UtLvWogbI6/OwlmgFmy+dNflrFZsjVRSqvZxTl2wtF7bf6R9VQutQoVQRGVdbLK vwgZuxilUXpHQ== Message-ID: <8c70259a-94ed-415c-89c1-572145c64670@kernel.org> Date: Thu, 17 Sep 2026 17:29:48 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/1] mm/huge_memory: disallow raw PMD mappings of the huge zero page To: Kiryl Shutsemau , Lance Yang Cc: 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 References: <20260917121010.60966-1-lance.yang@linux.dev> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit 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? -- Cheers, David