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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kees Cook , Peter Zijlstra , Jann Horn , Pedro Falcato , Hugh Dickins , Pasha Tatashin , Pratyush Yadav , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Lance Yang , Rik van Riel , Harry Yoo , Alistair Popple , Nico Pache , Ryan Roberts , Dev Jain , Usama Arif , Kiryl Shutsemau , Matthew Brost , John Hubbard , Peter Xu , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Oscar Salvador , Minchan Kim , Xu Xin , Chengming Zhou , Chris Li , Kemeng Shi , Nhat Pham , Youngjun Park , Gregory Price , Joshua Hahn , Rakie Kim , Ying Huang , Jason Gunthorpe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, stable@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-44-6f74bec9a5bb@kernel.org> To: "David Hildenbrand (Arm)" X-Mailer: Apple Mail (2.3901.100.1.1.12) X-Rspamd-Queue-Id: 9F331180005 X-Stat-Signature: pur4uyx897ayk6iqptsfpayujrhgkxx1 X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,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-Rspamd-Server: rspam09 X-HE-Tag: 1793094530-196512 X-HE-Meta: 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 Va14aXun GneFfRt+fW3F773O/lU7Nu7iGTgZlQ53tZ+QePcKDWOVnib4HNd0a7rIc6n80kGu0Ci4l+Ttro5s+QOY9I32fSIxPu5X26p0J1hny57SzFJzLUvCJLK5r7DMN88AhHcSbeU1F5jSnEM7ExIs/hNfc5zTN4zNIarsFzmss21FiQJpYjZZYWrrZZXsnJ03ujBvet0KRBE2WjruxHZZTyxLTJwBUnAeMalzP7PDVyTmml6H5/1bfHBiBdX++KwqtgW+xFaj4rgrfw09IgTiWFmEPxKnia1tZlyzSAu4rOXvXkvVYDgCag/djRwRFdYUOvSsIPTAj604odcbBhgYcpcxBQ1r+CQ1APh0Y15Xy450fqM7WEybDOBlMA78mqaAk6KMhO64ZfMw+snd/l/X5bSGtdCPkIYhNP0Tq1YkYmmWY2Z0VTrnuIiI0kMG2BYcHERFRxOmIU9xkyESf0aOKJIBcoZajb8lYl9Vi866L58XGJhNYrAOSd6/yZraA8WIyQatSs6Gz 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 Oct 27, 2026, at 07:18, David Hildenbrand (Arm) = wrote: >=20 > From: Rik van Riel >=20 > When a driver calls dma_free_contiguous() before quiescing DMA, the > page might still have a reference from the device. > put_page_testzero() there returns false, WARN fires, but the code = proceeds > to free_contig_frozen_range() putting a live page onto buddy and = clearing > the bitmap. A subsequent allocation can hand the same PFN to a new > owner while the original holder still references it. >=20 > A concurrent put_page() that drops the last reference between the > testzero loop and free_contig_frozen_range() can double-queue the page > via page->lru, corrupting buddy lists. >=20 > Avoid the corruption by not freeing a CMA region if any of the > pages inside are still in use. >=20 > Make it explicit in the warning that the driver allowed a leak. >=20 > While at it, use page_ref_freeze() to make the semantics clearer and > switch to pr_warn_ratelimited(). >=20 > Fixes: 9bda131c6093 ("mm: cma: add cma_alloc_frozen{_compound}()") > Cc: stable@vger.kernel.org > Signed-off-by: Rik van Riel > Link: https://patch.msgid.link/20260811132045.5f114772@fangorn > [ david: use page_ref_freeze() + pr_warn_ratelimited() ] > Signed-off-by: David Hildenbrand (Arm) Acked-by: Muchun Song Thanks