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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-Archived-By: 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> X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: BF90CC0005 X-Stat-Signature: shkoojazh64dn7gde9aqs6nsnqeda6zi X-Spam-Status: No, score=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1792579450-25353 X-HE-Meta: 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 OdqTBHIh 5PAWBt/Rv5kl3tR1CsPzjLfblUbEMvSXAqvSldmxmBhpQn6AgPAZ4NyFwpB1UW1Kg/P5Od5CP6SPtp0WV1OnUBn2kbqSx4Xgw6g5zp9RwhlPOVhz9axYiZhrP4Rl+TBZFrY3/JZFyE0EJsiHVFiNMPkzCHSutlXeUOYOHhiIZvXdTcEB6cfD4eRvcsw2uVUUU7uMgcXGD6Gx0NyhYGItjrOaMybh7lIBesLIm7DMySnMGTm9XXQzmRjRxznjXTbG4FUIf/ggimqHsbW5lZ9rHyJyDcv07K/5Bks6Wc3AhP4q6NICgNrfD0qKSVMoAzqxlpThMjLsIpWgg0khjUdFJ2LAs4x5bb0BIKxH+mO1TvvnbD+wv8CKR3QNDPa8iEERprsp23pe024ym6IeNYEAEuQaljMChZgLR3aoUd+loAb6UM1w= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 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