From: Peter Xu <peterx@redhat.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: David Hildenbrand <david@redhat.com>,
Pantelis Antoniou <p.antoniou@partner.samsung.com>,
Andrew Morton <akpm@linux-foundation.org>,
mm-commits@vger.kernel.org, wade.farnsworth@siemens.com,
jhubbard@nvidia.com, c.briere@samsung.com, artem.k@samsung.com,
David Howells <dhowells@redhat.com>
Subject: Re: + fix-zero-copy-i-o-on-__get_user_pages-allocated-pages.patch added to mm-hotfixes-unstable branch
Date: Thu, 8 May 2025 15:39:56 -0400 [thread overview]
Message-ID: <aB0IjHLKnxk_opq0@x1.local> (raw)
In-Reply-To: <20250508191215.GB138689@ziepe.ca>
On Thu, May 08, 2025 at 04:12:15PM -0300, Jason Gunthorpe wrote:
> AFAIK KVM is doing this wonky thing using mmu notifiers, it doesn't
> take page references on pte special pages..
I checked the latest, I think you're right at least on the latest master
branch.. IIUC it's behavior on refcounting changed only last year after
Sean's 3dd48ecfac7f ("KVM: Provide refcounted page as output field in
struct kvm_follow_pfn").
To me, taking the refcount has one tiny little "benefit" of avoiding the
UAF you mentioned in the other email. But I agree the whole thing is still
pretty wonky.
--
Peter Xu
next prev parent reply other threads:[~2025-05-08 19:40 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-07 21:55 + fix-zero-copy-i-o-on-__get_user_pages-allocated-pages.patch added to mm-hotfixes-unstable branch Andrew Morton
2025-05-08 14:16 ` Peter Xu
2025-05-08 14:36 ` Pantelis Antoniou
2025-05-08 15:08 ` Peter Xu
2025-05-08 15:10 ` David Hildenbrand
2025-05-08 15:27 ` Pantelis Antoniou
2025-05-08 15:40 ` David Hildenbrand
2025-05-08 15:48 ` Pantelis Antoniou
2025-05-08 16:25 ` Pantelis Antoniou
2025-05-08 17:35 ` Jason Gunthorpe
2025-05-08 17:47 ` Pantelis Antoniou
2025-05-08 18:01 ` Jason Gunthorpe
2025-05-08 18:02 ` David Hildenbrand
2025-05-08 18:11 ` Pantelis Antoniou
2025-05-08 18:26 ` David Hildenbrand
2025-05-08 18:47 ` Peter Xu
2025-05-08 19:04 ` David Hildenbrand
2025-05-08 19:06 ` Jason Gunthorpe
2025-05-08 19:08 ` Peter Xu
2025-05-08 19:12 ` Jason Gunthorpe
2025-05-08 19:16 ` David Hildenbrand
2025-05-08 19:39 ` Peter Xu [this message]
2025-05-08 19:14 ` David Hildenbrand
2025-05-08 19:19 ` Jason Gunthorpe
2025-05-08 19:34 ` David Hildenbrand
2025-05-09 16:30 ` Pantelis Antoniou
2025-05-09 17:11 ` John Hubbard
2025-05-09 17:33 ` Jason Gunthorpe
2025-05-09 17:50 ` Pantelis Antoniou
2025-05-09 18:39 ` Jason Gunthorpe
2025-05-08 19:11 ` Jason Gunthorpe
2025-05-08 15:17 ` Pantelis Antoniou
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