From: Jason Gunthorpe <jgg@ziepe.ca>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "DRI Development" <dri-devel@lists.freedesktop.org>,
LKML <linux-kernel@vger.kernel.org>,
kvm@vger.kernel.org, "Linux MM" <linux-mm@kvack.org>,
"Linux ARM" <linux-arm-kernel@lists.infradead.org>,
linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
"open list:DMA BUFFER SHARING FRAMEWORK"
<linux-media@vger.kernel.org>,
linux-s390@vger.kernel.org,
"Dan Williams" <dan.j.williams@intel.com>,
"Kees Cook" <keescook@chromium.org>,
"Rik van Riel" <riel@redhat.com>,
"Benjamin Herrensmidt" <benh@kernel.crashing.org>,
"Dave Airlie" <airlied@linux.ie>,
"Hugh Dickins" <hugh@veritas.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"John Hubbard" <jhubbard@nvidia.com>,
"Jérôme Glisse" <jglisse@redhat.com>, "Jan Kara" <jack@suse.cz>,
"Daniel Vetter" <daniel.vetter@intel.com>
Subject: Re: [PATCH 07/13] mm: close race in generic_access_phys
Date: Wed, 7 Oct 2020 20:21:17 -0300 [thread overview]
Message-ID: <20201007232117.GB5177@ziepe.ca> (raw)
In-Reply-To: <CAKMK7uH3P-6zs5MVceFD7872owqtcktqsTaQAOKNyaBg4_w=aA@mail.gmail.com>
On Wed, Oct 07, 2020 at 08:01:42PM +0200, Daniel Vetter wrote:
> I think it'd fix the bug, until someone wires ->access up for
> drivers/gpu, or the next subsystem. This is also just for ptrace, so
> we really don't care when we stall the vm badly and other silly
> things. So I figured the somewhat ugly, but full generic solution is
> the better one, so that people who want to be able to ptrace
> read/write their iomem mmaps can just sprinkle this wherever they feel
> like.
>
> But yeah if we go with most minimal fix, i.e. only trying to fix the
> current users, then your thing should work and is simpler. But it
> leaves the door open for future problems.
The only other idea I had was to fully make the 'vma of __iomem
memory' some generic utility, completely take over the vm_ops.
We did something like this in RDMA, what I found was even just
implementing mmap() using the kernel helpers turned out to be pretty
tricky, many drivers did it wrong in small ways.
Jason
next prev parent reply other threads:[~2020-10-07 23:21 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-07 16:44 [PATCH 00/13] follow_pfn and other iomap races Daniel Vetter
2020-10-07 16:44 ` [PATCH 01/13] drm/exynos: Stop using frame_vector helpers Daniel Vetter
2020-10-07 20:32 ` John Hubbard
2020-10-07 21:32 ` Daniel Vetter
2020-10-07 21:36 ` John Hubbard
2020-10-07 21:50 ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 02/13] drm/exynos: Use FOLL_LONGTERM for g2d cmdlists Daniel Vetter
2020-10-07 20:43 ` John Hubbard
2020-10-07 16:44 ` [PATCH 03/13] misc/habana: Stop using frame_vector helpers Daniel Vetter
2020-10-07 20:38 ` John Hubbard
2020-10-07 16:44 ` [PATCH 04/13] misc/habana: Use FOLL_LONGTERM for userptr Daniel Vetter
2020-10-07 20:46 ` John Hubbard
2020-10-07 16:44 ` [PATCH 05/13] mm/frame-vector: Use FOLL_LONGTERM Daniel Vetter
2020-10-07 16:53 ` Jason Gunthorpe
2020-10-07 17:12 ` Daniel Vetter
2020-10-07 17:33 ` Jason Gunthorpe
2020-10-07 21:13 ` John Hubbard
2020-10-07 21:30 ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 06/13] media: videobuf2: Move frame_vector into media subsystem Daniel Vetter
2020-10-07 22:18 ` John Hubbard
2020-10-07 16:44 ` [PATCH 07/13] mm: close race in generic_access_phys Daniel Vetter
2020-10-07 17:27 ` Jason Gunthorpe
2020-10-07 18:01 ` Daniel Vetter
2020-10-07 23:21 ` Jason Gunthorpe [this message]
2020-10-08 0:44 ` John Hubbard
2020-10-08 7:23 ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 08/13] s390/pci: Remove races against pte updates Daniel Vetter
2020-10-08 16:44 ` Gerald Schaefer
2020-10-08 17:16 ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 09/13] PCI: obey iomem restrictions for procfs mmap Daniel Vetter
2020-10-07 18:46 ` Bjorn Helgaas
2020-10-07 16:44 ` [PATCH 10/13] PCI: revoke mappings like devmem Daniel Vetter
2020-10-07 18:41 ` Bjorn Helgaas
2020-10-07 19:24 ` Daniel Vetter
2020-10-07 19:33 ` Dan Williams
2020-10-07 19:47 ` Daniel Vetter
2020-10-07 22:23 ` Dan Williams
2020-10-07 22:29 ` Dan Williams
2020-10-08 8:09 ` Daniel Vetter
2020-10-07 23:24 ` Jason Gunthorpe
2020-10-08 7:31 ` Daniel Vetter
2020-10-08 7:49 ` Dan Williams
2020-10-08 8:13 ` Daniel Vetter
2020-10-08 8:35 ` Dan Williams
2020-10-08 12:41 ` Jason Gunthorpe
2020-10-07 16:44 ` [PATCH 11/13] mm: add unsafe_follow_pfn Daniel Vetter
2020-10-07 17:36 ` Jason Gunthorpe
2020-10-07 18:10 ` Daniel Vetter
2020-10-07 19:00 ` Jason Gunthorpe
2020-10-07 19:38 ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 12/13] media/videbuf1|2: Mark follow_pfn usage as unsafe Daniel Vetter
2020-10-07 16:44 ` [PATCH 13/13] vfio/type1: Mark follow_pfn " Daniel Vetter
2020-10-07 17:39 ` Jason Gunthorpe
2020-10-07 18:14 ` Daniel Vetter
2020-10-07 18:47 ` Jason Gunthorpe
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