From: Kiryl Shutsemau <kas@kernel.org>
To: "David Hildenbrand (Arm)" <david@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Liam R. Howlett" <liam@infradead.org>,
Lorenzo Stoakes <ljs@kernel.org>,
Vlastimil Babka <vbabka@kernel.org>,
Jann Horn <jannh@google.com>, Pedro Falcato <pfalcato@suse.de>,
Muchun Song <muchun.song@linux.dev>,
Oscar Salvador <osalvador@suse.de>,
Miaohe Lin <linmiaohe@huawei.com>,
Naoya Horiguchi <nao.horiguchi@gmail.com>,
Adam Litke <agl@us.ibm.com>, Mel Gorman <mel@csn.ul.ie>,
Rik van Riel <riel@surriel.com>, Peter Xu <peterx@redhat.com>,
"Mike Rapoport (Microsoft)" <rppt@kernel.org>,
Josef Bacik <josef@toxicpanda.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH 07/10] mm/hugetlb: tolerate uffd bits set without uffd for PROT_NONE PTEs
Date: Wed, 21 Oct 2026 11:44:01 +0100 [thread overview]
Message-ID: <atiXUuyXM89u-XBV@thinkstation> (raw)
In-Reply-To: <20261015-urgent_fixes-v1-7-42796911043b@kernel.org>
On Thu, Oct 15, 2026 at 06:07:13PM +0200, David Hildenbrand (Arm) wrote:
> The whole uffd handling when a VMA is unregistered from UFFD is shaky:
> there are still some scenarios where we might have stale uffd PTE bits
> in VMAs no longer registered for UFFD, which confuses other code.
>
> Let's just tolerate that for now and simply clear the PTE bit. Add a
> TODO to really clean up any uffd leftovers when unregistering a VMA from
> userfaultfd.
>
> The handling is now more similar to what we have in handle_pte_fault().
>
> Fixes: 2d427bb01639 ("mm/userfaultfd: add RWP fault delivery and expose UFFDIO_REGISTER_MODE_RWP")
> Cc: stable@vger.kernel.org
> Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2026-10-21 10:44 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-15 16:07 [PATCH 00/10] mm: various (urgent?) fixes David Hildenbrand (Arm)
2026-10-15 16:07 ` [PATCH 01/10] mm/vma: don't leak the commit charge on mmap failure David Hildenbrand (Arm)
2026-10-15 17:54 ` Pedro Falcato
2026-10-15 18:53 ` David Hildenbrand (Arm)
2026-10-16 8:34 ` Jose A. Perez de Azpillaga
2026-10-18 6:06 ` Lance Yang
2026-10-15 16:07 ` [PATCH 02/10] mm/hugetlb: fix use-after-free of a new anon folio David Hildenbrand (Arm)
2026-10-16 7:16 ` Muchun Song
2026-10-18 6:16 ` Lance Yang
2026-10-15 16:07 ` [PATCH 03/10] mm/hugetlb: fix use-after-free in hugetlb_mfill_atomic_pte() David Hildenbrand (Arm)
2026-10-16 7:18 ` Muchun Song
2026-10-18 6:22 ` Lance Yang
2026-10-15 16:07 ` [PATCH 04/10] mm/hugetlb: unmap the page where the other VMA maps it David Hildenbrand (Arm)
2026-10-16 9:49 ` Muchun Song
2026-10-18 6:43 ` Lance Yang
2026-10-15 16:07 ` [PATCH 05/10] mm/hugetlb: don't clear the resv_map of a VMA whose lock is held David Hildenbrand (Arm)
2026-10-16 9:52 ` Muchun Song
2026-10-18 6:53 ` Lance Yang
2026-10-15 16:07 ` [PATCH 06/10] mm/hugetlb: fix endless write fault on a leftover uffd bit David Hildenbrand (Arm)
2026-10-15 20:10 ` Lorenzo Stoakes (ARM)
2026-10-18 7:11 ` Lance Yang
2026-10-15 16:07 ` [PATCH 07/10] mm/hugetlb: tolerate uffd bits set without uffd for PROT_NONE PTEs David Hildenbrand (Arm)
2026-10-15 20:13 ` Lorenzo Stoakes (ARM)
2026-10-18 7:59 ` Lance Yang
2026-10-21 10:44 ` Kiryl Shutsemau [this message]
2026-10-15 16:07 ` [PATCH 08/10] mm/hugetlb: tolerate UFFD_WP markers outside uffd-wp VMAs David Hildenbrand (Arm)
2026-10-15 19:47 ` Lorenzo Stoakes (ARM)
2026-10-18 8:07 ` Lance Yang
2026-10-15 16:07 ` [PATCH 09/10] mm/hugetlb: don't leave a uffd-wp marker when zapping an RWP entry David Hildenbrand (Arm)
2026-10-15 19:45 ` Lorenzo Stoakes (ARM)
2026-10-18 8:21 ` Lance Yang
2026-10-21 10:45 ` Kiryl Shutsemau
2026-10-15 16:07 ` [PATCH 10/10] mm/mremap: fix calling fixup_hugetlb_reservations() on the wrong VMA David Hildenbrand (Arm)
2026-10-16 9:53 ` Muchun Song
2026-10-18 8:34 ` Lance Yang
2026-10-19 12:24 ` David Hildenbrand (Arm)
2026-10-16 7:15 ` [PATCH 00/10] mm: various (urgent?) fixes Muchun Song
2026-10-16 7:40 ` David Hildenbrand (Arm)
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