From: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
To: Christoph Hellwig <hch@lst.de>,
Serge Belyshev <belyshev@depni.sinp.msu.ru>
Cc: Peter Zijlstra <peterz@infradead.org>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
intel-gfx@lists.freedesktop.org,
Chris Wilson <chris@chris-wilson.co.uk>,
linux-mm@kvack.org, dri-devel@lists.freedesktop.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [Intel-gfx] [PATCH 4/4] i915: fix remap_io_sg to verify the pgprot
Date: Mon, 17 May 2021 23:46:35 +0200 [thread overview]
Message-ID: <976fb38a-7780-6ca6-d602-a5f02c0938c9@linux.intel.com> (raw)
In-Reply-To: <20210517131137.GA19451@lst.de>
On 5/17/21 3:11 PM, Christoph Hellwig wrote:
> On Mon, May 17, 2021 at 04:09:42PM +0300, Serge Belyshev wrote:
>> Christoph Hellwig <hch@lst.de> writes:
>>
>>> As an ad-hoc experiment: can you replace the call to remap_pfn_range
>>> with remap_pfn_range_notrack (and export it if you build i915 modular)
>>> in remap_io_sg and see if that makes any difference?
>> That worked, thanks -- no artifacts seen.
> Looks like it is caused by the validation failure then. Which means the
> existing code is doing something wrong in its choice of the page
> protection bit. I really need help from the i915 maintainers here..
Hmm,
Apart from the caching aliasing Mattew brought up, doesn't the
remap_pfn_range_xxx() family require the mmap_sem held in write mode
since it modifies the vma structure? remap_io_sg() is called from the
fault handler with the mmap_sem held in read mode only.
/Thomas
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
next prev parent reply other threads:[~2021-05-17 21:46 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-26 5:55 add remap_pfn_range_notrack instead of reinventing it in i915 v2 Christoph Hellwig
2021-03-26 5:55 ` [PATCH 1/4] mm: add remap_pfn_range_notrack Christoph Hellwig
2021-03-26 5:55 ` [PATCH 2/4] mm: add a io_mapping_map_user helper Christoph Hellwig
2021-10-20 15:40 ` [Intel-gfx] " Lucas De Marchi
2021-10-20 19:37 ` Peter Zijlstra
2021-10-21 6:18 ` Christoph Hellwig
2021-03-26 5:55 ` [PATCH 3/4] i915: use io_mapping_map_user Christoph Hellwig
2021-03-26 5:55 ` [PATCH 4/4] i915: fix remap_io_sg to verify the pgprot Christoph Hellwig
2021-05-08 19:33 ` [Intel-gfx] " youling257
2021-05-10 8:58 ` Christoph Hellwig
2021-05-16 16:06 ` Serge Belyshev
2021-05-17 12:37 ` Christoph Hellwig
2021-05-17 13:09 ` Serge Belyshev
2021-05-17 13:11 ` Christoph Hellwig
2021-05-17 17:06 ` [Intel-gfx] " Matthew Auld
2021-05-18 13:21 ` Christoph Hellwig
2021-05-18 15:00 ` Matthew Auld
2021-05-19 5:46 ` Thomas Hellström (Intel)
2021-05-17 21:46 ` Thomas Hellström [this message]
2021-05-18 6:46 ` Thomas Hellström
2021-05-18 13:24 ` Christoph Hellwig
2021-05-18 13:33 ` Thomas Hellström
2021-05-18 13:23 ` Christoph Hellwig
2021-05-19 5:51 ` Thomas Hellström
2021-04-08 10:36 ` add remap_pfn_range_notrack instead of reinventing it in i915 v2 Daniel Vetter
2021-04-08 11:28 ` Christoph Hellwig
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