From mboxrd@z Thu Jan  1 00:00:00 1970
From: Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH mm-unstable v1 20/20] mm: rename FOLL_FORCE to FOLL_PTRACE
Date: Thu, 17 Nov 2022 14:58:19 -0800
Message-ID: <202211171439.CDE720EAD@keescook>
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To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>, linux-kernel@vger.kernel.org, x86@kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>, Jason Gunthorpe <jgg@ziepe.ca>, John Hubbard <jhubbard@nvidia.com>, Peter Xu <peterx@redhat.com>, Greg Kroah-Hartman <gregkh>

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