linux-kernel - Re: [PATCH v2] mm/mm_init: Don't iterate pages below ARCH_PFN

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: <20250420135709.732883ee775ad8b41fb668ca@linux-foundation.org>
Date: Sun, 20 Apr 2025 13:57:09 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: Ruihan Li <lrh2000@....edu.cn>
Cc: Mike Rapoport <rppt@...nel.org>, linux-mm@...ck.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] mm/mm_init: Don't iterate pages below
 ARCH_PFN_OFFSET

On Sat, 19 Apr 2025 20:28:01 +0800 Ruihan Li <lrh2000@....edu.cn> wrote:

> If ARCH_PFN_OFFSET is very large (e.g., something like 2^64-2GiB if the
> kernel is used as a library and loaded at a very high address), the
> pointless iteration for pages below ARCH_PFN_OFFSET will take a very
> long time, and the kernel will look stuck at boot time.
> 
> This commit sets the initial value of pfn_hole to ARCH_PFN_OFFSET, which
> avoids the problematic and useless iteration mentioned above.
> 
> This problem has existed since commit 907ec5fca3dc ("mm: zero remaining
> unavailable struct pages").
> 
> Signed-off-by: Ruihan Li <lrh2000@....edu.cn>
> ---
> Link to v1:
>  - https://lore.kernel.org/linux-mm/20250418162727.1535335-1-lrh2000@pku.edu.cn/
> Changes since v1:
>  - Removed the unnecessary Fixes tag.

Why was the Fixes: considered unnecessary?  It seems to be useful
information?