From: "David Hildenbrand (Arm)" <david@kernel.org>
To: "Boone, Max" <mboone@akamai.com>, Alex Williamson <alex@shazbot.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>, Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Tottenham, Max" <mtottenh@akamai.com>,
"Hunt, Joshua" <johunt@akamai.com>,
"Pelland, Matt" <mpelland@akamai.com>
Subject: Re: [RFC 1/1] mm/pagewalk: don't split device-backed huge pfnmaps
Date: Wed, 11 Mar 2026 10:59:10 +0100 [thread overview]
Message-ID: <5fb9beef-b6fe-401a-aa24-aade48b795d4@kernel.org> (raw)
In-Reply-To: <6CBB0401-26DD-4EF9-949C-54BEAD3ABA33@akamai.com>
> The -EINVAL originates from:
>
> vfio_dma_do_map -> vfio_pin_map_dma -> vfio_pin_pages_remote
> -> vaddr_get_pfns -> pin_user_pages_remote (mm/gup.c)
>
> Possibly that’s also the origin of the concurrent PUD modification that requires
> the retry in the walker in this patch.
We'd have to find out why we manage to trigger a -EINVAL here. I don't
see how anything that this patch does could trigger that. So maybe a
problem in user space? (calling it on unsupported VMAs?).
--
Cheers,
David
next prev parent reply other threads:[~2026-03-11 9:59 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-09 17:49 [RFC 0/1] Avoid pagewalk hugepage-split race with VFIO DMA set Max Boone
2026-03-09 17:49 ` [RFC 1/1] mm/pagewalk: don't split device-backed huge pfnmaps Max Boone
2026-03-09 20:19 ` David Hildenbrand (Arm)
2026-03-09 22:47 ` Boone, Max
2026-03-09 23:02 ` Boone, Max
2026-03-10 9:11 ` David Hildenbrand (Arm)
2026-03-10 11:38 ` Boone, Max
2026-03-10 15:19 ` David Hildenbrand (Arm)
2026-03-11 9:42 ` Boone, Max
2026-03-11 9:59 ` David Hildenbrand (Arm) [this message]
2026-03-11 10:34 ` Boone, Max
2026-03-11 10:45 ` David Hildenbrand (Arm)
2026-03-11 11:14 ` Boone, Max
2026-03-11 11:59 ` David Hildenbrand (Arm)
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