From: Ralph Campbell <rcampbell@nvidia.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
nouveau@lists.freedesktop.org,
"Jérôme Glisse" <jglisse@redhat.com>,
"Jason Gunthorpe" <jgg@mellanox.com>,
"Andrew Morton" <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/2] mm/hmm: hmm_range_fault() NULL pointer bug
Date: Mon, 26 Aug 2019 11:02:12 -0700 [thread overview]
Message-ID: <e2ecc1a7-0d2f-5957-e6cb-b3c86c085d80@nvidia.com> (raw)
In-Reply-To: <20190824223754.GA21891@lst.de>
On 8/24/19 3:37 PM, Christoph Hellwig wrote:
> On Fri, Aug 23, 2019 at 03:17:52PM -0700, Ralph Campbell wrote:
>> Although hmm_range_fault() calls find_vma() to make sure that a vma exists
>> before calling walk_page_range(), hmm_vma_walk_hole() can still be called
>> with walk->vma == NULL if the start and end address are not contained
>> within the vma range.
>
> Should we convert to walk_vma_range instead? Or keep walk_page_range
> but drop searching the vma ourselves?
>
> Except for that the patch looks good to me:
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
>
I think keeping the call to walk_page_range() makes sense.
Jason is hoping to be able to snapshot a range with & without vmas
and have the pfns[] filled with empty/valid entries as appropriate.
I plan to repost my patch changing hmm_range_fault() to use
walk.test_walk which will remove the call to find_vma().
Jason had some concerns about testing it so that's why I have
been working on some HMM self tests before resending it.
next prev parent reply other threads:[~2019-08-26 18:02 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-23 22:17 [PATCH 0/2] mm/hmm: two bug fixes for hmm_range_fault() Ralph Campbell
2019-08-23 22:17 ` [PATCH 1/2] mm/hmm: hmm_range_fault() NULL pointer bug Ralph Campbell
2019-08-24 22:37 ` Christoph Hellwig
2019-08-26 18:02 ` Ralph Campbell [this message]
2019-08-26 18:09 ` Jason Gunthorpe
2019-08-26 18:21 ` Ralph Campbell
2019-08-23 22:17 ` [PATCH 2/2] mm/hmm: hmm_range_fault() infinite loop Ralph Campbell
2019-08-24 22:39 ` Christoph Hellwig
2019-08-27 18:41 ` Jason Gunthorpe
2019-08-27 20:16 ` Ralph Campbell
2019-08-27 22:22 ` Jason Gunthorpe
2019-08-27 22:48 ` [PATCH 0/2] mm/hmm: two bug fixes for hmm_range_fault() Jason Gunthorpe
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