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Howlett" , Lorenzo Stoakes , Vlastimil Babka , Jann Horn , Pedro Falcato , Muchun Song , Oscar Salvador , Miaohe Lin , Naoya Horiguchi , Adam Litke , Mel Gorman , Rik van Riel , Peter Xu , "Mike Rapoport (Microsoft)" , Josef Bacik , 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 Message-ID: References: <20261015-urgent_fixes-v1-0-42796911043b@kernel.org> <20261015-urgent_fixes-v1-7-42796911043b@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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) Acked-by: Kiryl Shutsemau (Meta) -- Kiryl Shutsemau / Kirill A. Shutemov