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From: Mike Kravetz <mike.kravetz@oracle.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Peter Xu <peterx@redhat.com>, John Hubbard <jhubbard@nvidia.com>,
	syzbot+f0b97304ef90f0d0b1dc@syzkaller.appspotmail.com
Subject: Re: [PATCH v1] mm/gup: disallow FOLL_FORCE|FOLL_WRITE on hugetlb mappings
Date: Mon, 31 Oct 2022 15:13:03 -0700	[thread overview]
Message-ID: <Y2BIbyxT0Bh6bCUr@monkey> (raw)
In-Reply-To: <Y1/0e12ZJT6+N0kI@nvidia.com>

On 10/31/22 13:14, Jason Gunthorpe wrote:
> On Mon, Oct 31, 2022 at 04:25:24PM +0100, David Hildenbrand wrote:
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: Mike Kravetz <mike.kravetz@oracle.com>
> > Cc: Peter Xu <peterx@redhat.com>
> > Cc: John Hubbard <jhubbard@nvidia.com>
> > Cc: Jason Gunthorpe <jgg@nvidia.com>
> > Reported-by: syzbot+f0b97304ef90f0d0b1dc@syzkaller.appspotmail.com
> > Signed-off-by: David Hildenbrand <david@redhat.com>
> > ---
> > 
> > I assume this has been broken at least since 2014, when mm/gup.c came to
> > life. I failed to come up with a suitable Fixes tag quickly.
> 
> I'm worried this would break RDMA over hugetlbfs maps - which is a
> real thing people do.

Yes, it is a real thing.  Unfortunately, I do not know exactly how it is used.

> 
> MikeK do you have test cases?

Sorry, I do not have any test cases.

I can ask one of our product groups about their usage.  But, that would
certainly not be a comprehensive view.
-- 
Mike Kravetz


  reply	other threads:[~2022-10-31 22:13 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-31 15:25 [PATCH v1] mm/gup: disallow FOLL_FORCE|FOLL_WRITE on hugetlb mappings David Hildenbrand
2022-10-31 16:14 ` Jason Gunthorpe
2022-10-31 22:13   ` Mike Kravetz [this message]
2022-11-21  8:05     ` David Hildenbrand
2022-11-21 21:33       ` Andrew Morton
2022-11-22  9:05         ` David Hildenbrand
2022-11-22 17:41           ` Mike Kravetz
2022-11-22 17:59             ` Jason Gunthorpe
2022-11-22 23:03               ` Andrew Morton
2022-11-22 23:48                 ` Mike Kravetz
2022-11-23  8:40                   ` David Hildenbrand
2022-11-02  9:14   ` David Hildenbrand
2022-11-02 11:38     ` Jason Gunthorpe

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