linux-kernel - Re: [PATCH v10 4/8] highmem: do range clearing in clear_user

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <e9033bc2-9a85-45de-a005-b9d12eb81f66@kernel.org>
Date: Thu, 18 Dec 2025 08:15:07 +0100
From: "David Hildenbrand (Red Hat)" <david@...nel.org>
To: Ankur Arora <ankur.a.arora@...cle.com>, linux-kernel@...r.kernel.org,
 linux-mm@...ck.org, x86@...nel.org
Cc: akpm@...ux-foundation.org, bp@...en8.de, dave.hansen@...ux.intel.com,
 hpa@...or.com, mingo@...hat.com, mjguzik@...il.com, luto@...nel.org,
 peterz@...radead.org, tglx@...utronix.de, willy@...radead.org,
 raghavendra.kt@....com, chleroy@...nel.org, ioworker0@...il.com,
 boris.ostrovsky@...cle.com, konrad.wilk@...cle.com
Subject: Re: [PATCH v10 4/8] highmem: do range clearing in
 clear_user_highpages()

On 12/15/25 21:49, Ankur Arora wrote:
> Use the range clearing primitive clear_user_pages() when clearing
> contiguous pages in clear_user_highpages().
> 
> We can safely do that when we have !CONFIG_HIGHMEM and when the
> architecture does not have clear_user_highpage.
> 
> The first is necessary because not doing intermediate maps for
> pages lets contiguous page ranges stay contiguous. The second,
> because if the architecture has clear_user_highpage(), it likely
> needs flushing magic when clearing the page, magic that we aren't
> privy to.
> 
> Signed-off-by: Ankur Arora <ankur.a.arora@...cle.com>
> ---

Can't you squash #4 into #2 if you move #3 in front of them? Or is there 
a dependency with #2 that I am missing?

-- 
Cheers

David