From: Kees Cook <keescook@chromium.org>
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>
Subject: Re: [PATCH mm-unstable v1 20/20] mm: rename FOLL_FORCE to FOLL_PTRACE
Date: Thu, 17 Nov 2022 16:31:24 -0800 [thread overview]
Message-ID: <202211171630.8EABF5EDD@keescook> (raw)
In-Reply-To: <CAHk-=wjykbz-4xVTWF7vkvGJnFoTSXNVeMzfsXaLnGm3CRd8rQ@mail.gmail.com>
On Thu, Nov 17, 2022 at 03:20:01PM -0800, Linus Torvalds wrote:
> On Thu, Nov 17, 2022 at 2:58 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > 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.
>
> Yeah, it does seem entirely superfluous.
>
> It's been there since the very beginning (although in that original
> commit b6a2fea39318 it was there as a '1' to the 'force' argument to
> get_user_pages()).
>
> I *think* it can be just removed. But as long as it exists, it should
> most definitely not be renamed to FOLL_PTRACE.
>
> There's a slight worry that it currently hides some other setup issue
> that makes it matter, since it's been that way so long, but I can't
> see what it is.
My test system boots happily with it removed. I'll throw it into -next
and see if anything melts...
--
Kees Cook
next prev parent reply other threads:[~2022-11-18 0:31 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-16 10:26 [PATCH mm-unstable v1 00/20] mm/gup: remove FOLL_FORCE usage from drivers (reliable R/O long-term pinning) David Hildenbrand
2022-11-16 10:26 ` [PATCH mm-unstable v1 01/20] selftests/vm: anon_cow: prepare for non-anonymous COW tests David Hildenbrand
2022-11-18 16:20 ` Vlastimil Babka
2022-11-16 10:26 ` [PATCH mm-unstable v1 02/20] selftests/vm: cow: basic COW tests for non-anonymous pages David Hildenbrand
2022-11-16 10:26 ` [PATCH mm-unstable v1 03/20] selftests/vm: cow: R/O long-term pinning reliability tests for non-anon pages David Hildenbrand
2022-11-16 10:26 ` [PATCH mm-unstable v1 04/20] mm: add early FAULT_FLAG_UNSHARE consistency checks David Hildenbrand
2022-11-18 16:45 ` Vlastimil Babka
2022-11-16 10:26 ` [PATCH mm-unstable v1 05/20] mm: add early FAULT_FLAG_WRITE " David Hildenbrand
2022-11-18 17:03 ` Vlastimil Babka
2022-11-16 10:26 ` [PATCH mm-unstable v1 06/20] mm: rework handling in do_wp_page() based on private vs. shared mappings David Hildenbrand
2022-11-22 14:20 ` Vlastimil Babka
2022-11-16 10:26 ` [PATCH mm-unstable v1 07/20] mm: don't call vm_ops->huge_fault() in wp_huge_pmd()/wp_huge_pud() for private mappings David Hildenbrand
[not found] ` <20221116102659.70287-8-david-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2022-11-22 14:50 ` Vlastimil Babka
2022-11-16 10:26 ` [PATCH mm-unstable v1 08/20] mm: extend FAULT_FLAG_UNSHARE support to anything in a COW mapping David Hildenbrand
2022-11-22 15:35 ` Vlastimil Babka
2022-11-16 10:26 ` [PATCH mm-unstable v1 09/20] mm/gup: reliable R/O long-term pinning in COW mappings David Hildenbrand
2022-11-16 10:42 ` Daniel Vetter
2022-11-22 16:29 ` Vlastimil Babka
2022-11-24 1:29 ` John Hubbard
2022-11-16 10:26 ` [PATCH mm-unstable v1 10/20] RDMA/umem: remove FOLL_FORCE usage David Hildenbrand
2022-11-17 0:45 ` Jason Gunthorpe
2022-11-16 10:26 ` [PATCH mm-unstable v1 11/20] RDMA/usnic: " David Hildenbrand
2022-11-17 0:45 ` Jason Gunthorpe
2022-11-16 10:26 ` [PATCH mm-unstable v1 12/20] RDMA/siw: " David Hildenbrand
2022-11-17 0:46 ` Jason Gunthorpe
2022-11-16 10:26 ` [PATCH mm-unstable v1 13/20] media: videobuf-dma-sg: " David Hildenbrand
2022-11-16 10:48 ` Daniel Vetter
2022-11-23 13:17 ` Hans Verkuil
2022-11-16 10:26 ` [PATCH mm-unstable v1 14/20] drm/etnaviv: " David Hildenbrand
2022-11-16 10:49 ` Daniel Vetter
2022-11-16 10:26 ` [PATCH mm-unstable v1 15/20] media: pci/ivtv: " David Hildenbrand
2022-11-23 13:18 ` Hans Verkuil
2022-11-16 10:26 ` [PATCH mm-unstable v1 16/20] mm/frame-vector: " David Hildenbrand
2022-11-16 10:50 ` Daniel Vetter
2022-11-23 13:26 ` Hans Verkuil
2022-11-23 14:28 ` Hans Verkuil
2022-11-27 10:35 ` David Hildenbrand
2022-11-28 8:17 ` Hans Verkuil
2022-11-28 8:18 ` David Hildenbrand
2022-11-28 8:26 ` Hans Verkuil
2022-11-28 8:57 ` Tomasz Figa
2022-11-28 22:59 ` Andrew Morton
2022-11-29 8:48 ` David Hildenbrand
2022-11-29 9:08 ` Hans Verkuil
2022-11-29 9:15 ` David Hildenbrand
2022-11-16 10:26 ` [PATCH mm-unstable v1 17/20] drm/exynos: " David Hildenbrand
2022-11-16 10:50 ` Daniel Vetter
2022-11-16 10:26 ` [PATCH mm-unstable v1 18/20] RDMA/hw/qib/qib_user_pages: " David Hildenbrand
2022-11-16 10:26 ` [PATCH mm-unstable v1 19/20] habanalabs: " David Hildenbrand
2022-11-16 10:26 ` [PATCH mm-unstable v1 20/20] mm: rename FOLL_FORCE to FOLL_PTRACE David Hildenbrand
2022-11-16 18:16 ` Linus Torvalds
2022-11-16 18:53 ` David Hildenbrand
2022-11-17 22:58 ` Kees Cook
2022-11-17 23:20 ` Linus Torvalds
2022-11-18 0:31 ` Kees Cook [this message]
2022-11-18 11:09 ` Peter Zijlstra
2022-11-18 22:29 ` Kees Cook
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