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: <CAHk-=wg2zJgy69j8n6C9T4YARkxcJ09SFkpMiqrCqhChf0s3NQ@mail.gmail.com>
Date: Wed, 5 Jun 2024 10:28:03 -0700
From: Linus Torvalds <torvalds@...ux-foundation.org>
To: Oleg Nesterov <oleg@...hat.com>
Cc: Ingo Molnar <mingo@...nel.org>, linux-kernel@...r.kernel.org, 
	Andy Lutomirski <luto@...capital.net>, Andrew Morton <akpm@...ux-foundation.org>, 
	Dave Hansen <dave@...1.net>, Peter Zijlstra <peterz@...radead.org>, Borislav Petkov <bp@...en8.de>, 
	"H . Peter Anvin" <hpa@...or.com>, Thomas Gleixner <tglx@...utronix.de>, Uros Bizjak <ubizjak@...il.com>
Subject: Re: [PATCH 3/3] x86/fpu: Remove init_task FPU state dependencies, add
 debugging warning

On Wed, 5 Jun 2024 at 09:27, Oleg Nesterov <oleg@...hat.com> wrote:
>
> Yes, but kernel_fpu_begin() never does save_fpregs_to_fpstate() if
> current->flags & PF_KTHREAD ?

Ahh, and init_thread does have PF_KTHREAD.

Ok, looks fine to me, except I think the commit message should be cleared up.

The whole sentence about

 "But the init task isn't supposed to be using the FPU in any case ..."

is just simply not true.

It should be more along the lines of "kernel threads don't need an FPU
save area, because their FPU use is not preemptible or reentrant and
they don't return to user space".

                Linus

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ