linux-kernel - Re: [PATCH 3.5] arm: make initialization of zero page independent of the memory map (was Re: [PATCH v2 22/28] arch, mm: consolidate initialization of nodes, zones and memory map)

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] [day] [month] [year] [list]

Message-Id: <20260108111919.ac5f811132672e760f47fbab@linux-foundation.org>
Date: Thu, 8 Jan 2026 11:19:19 -0800
From: Andrew Morton <akpm@...ux-foundation.org>
To: Mike Rapoport <rppt@...nel.org>
Cc: Klara Modin <klarasmodin@...il.com>, Alex Shi <alexs@...nel.org>,
 Alexander Gordeev <agordeev@...ux.ibm.com>, Andreas Larsson
 <andreas@...sler.com>, Borislav Petkov <bp@...en8.de>, Brian Cain
 <bcain@...nel.org>, "Christophe Leroy (CS GROUP)" <chleroy@...nel.org>,
 Catalin Marinas <catalin.marinas@....com>, "David S. Miller"
 <davem@...emloft.net>, Dave Hansen <dave.hansen@...ux.intel.com>, David
 Hildenbrand <david@...nel.org>, Dinh Nguyen <dinguyen@...nel.org>, Geert
 Uytterhoeven <geert@...ux-m68k.org>, Guo Ren <guoren@...nel.org>, Heiko
 Carstens <hca@...ux.ibm.com>, Helge Deller <deller@....de>, Huacai Chen
 <chenhuacai@...nel.org>, Ingo Molnar <mingo@...hat.com>, Johannes Berg
 <johannes@...solutions.net>, John Paul Adrian Glaubitz
 <glaubitz@...sik.fu-berlin.de>, Jonathan Corbet <corbet@....net>,
 "Liam R. Howlett" <Liam.Howlett@...cle.com>, Lorenzo Stoakes
 <lorenzo.stoakes@...cle.com>, Magnus Lindholm <linmag7@...il.com>, Matt
 Turner <mattst88@...il.com>, Max Filippov <jcmvbkbc@...il.com>, Michael
 Ellerman <mpe@...erman.id.au>, Michal Hocko <mhocko@...e.com>, Michal Simek
 <monstr@...str.eu>, Muchun Song <muchun.song@...ux.dev>, Oscar Salvador
 <osalvador@...e.de>, Palmer Dabbelt <palmer@...belt.com>, Pratyush Yadav
 <pratyush@...nel.org>, Richard Weinberger <richard@....at>, Russell King
 <linux@...linux.org.uk>, Stafford Horne <shorne@...il.com>, Suren
 Baghdasaryan <surenb@...gle.com>, Thomas Bogendoerfer
 <tsbogend@...ha.franken.de>, Thomas Gleixner <tglx@...utronix.de>, Vasily
 Gorbik <gor@...ux.ibm.com>, Vineet Gupta <vgupta@...nel.org>, Vlastimil
 Babka <vbabka@...e.cz>, Will Deacon <will@...nel.org>, x86@...nel.org,
 linux-alpha@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
 linux-csky@...r.kernel.org, linux-cxl@...r.kernel.org,
 linux-doc@...r.kernel.org, linux-hexagon@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-m68k@...ts.linux-m68k.org,
 linux-mips@...r.kernel.org, linux-mm@...ck.org,
 linux-openrisc@...r.kernel.org, linux-parisc@...r.kernel.org,
 linux-riscv@...ts.infradead.org, linux-s390@...r.kernel.org,
 linux-sh@...r.kernel.org, linux-snps-arc@...ts.infradead.org,
 linux-um@...ts.infradead.org, linuxppc-dev@...ts.ozlabs.org,
 loongarch@...ts.linux.dev, sparclinux@...r.kernel.org
Subject: Re: [PATCH 3.5] arm: make initialization of zero page independent
 of the memory map (was Re: [PATCH v2 22/28] arch, mm: consolidate
 initialization of nodes, zones and memory map)

On Sun, 4 Jan 2026 14:01:40 +0200 Mike Rapoport <rppt@...nel.org> wrote:

> Can you please stick this between patch 3 (arm: introduce
> arch_zone_limits_init()) and patch 4 (arm64: introduce
> arch_zone_limits_init())?

Did, thanks.  I made this a standalone patch rather than  a
squashable -fix.

> >From 35d016bbf5da7c08cc5c5547c85558fc50cb63aa Mon Sep 17 00:00:00 2001
> From: Klara Modin <klarasmodin@...il.com>
> Date: Sat, 3 Jan 2026 20:40:09 +0200
> Subject: [PATCH] arm: make initialization of zero page independent of the
>  memory map
> 
> Unlike most architectures, arm keeps a struct page pointer to the
> empty_zero_page and to initialize it requires conversion of a virtual
> address to page which makes it necessary to have memory map initialized
> before creating the empty_zero_page.
> 
> Make empty_zero_page a stataic array in BSS to decouple it's
> initialization from the initialization of the memory map.
> 
> This also aligns arm with vast majorty of architectures.

Russell, can you please update us on your concerns with this change?