linux-kernel - Re: [PATCH mm-unstable v1 20/20] mm: rename FOLL_FORCE to FOLL

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Date:   Thu, 17 Nov 2022 14:58:19 -0800
From:   Kees Cook <keescook@...omium.org>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     David Hildenbrand <david@...hat.com>, linux-kernel@...r.kernel.org,
        x86@...nel.org, linux-alpha@...r.kernel.org,
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        James Morris <jmorris@...ei.org>,
        "Serge E. Hallyn" <serge@...lyn.com>
Subject: Re: [PATCH mm-unstable v1 20/20] mm: rename FOLL_FORCE to FOLL_PTRACE

On Wed, Nov 16, 2022 at 10:16:34AM -0800, Linus Torvalds wrote:
> There _are_ also small random cases too, like get_cmdline(). Maybe
> that counts as ptrace, but the execve() case most definitely does not.

Oh, er, why does get_arg_page() even need FOLL_FORCE? This is writing the
new stack contents to the nascent brpm->vma, which was newly allocated
with VM_STACK_FLAGS, which an arch can override, but they all appear to include
VM_WRITE | VM_MAYWRITE.

-- 
Kees Cook