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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 , Muchun Song , Xu Xin , Chengming Zhou , Chris Li , Kemeng Shi , Nhat Pham , Youngjun Park , Gregory Price , Joshua Hahn , Rakie Kim , Ying Huang , Jason Gunthorpe Cc: 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, Josef Bacik , Muhammad Usama Anjum , "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3393; i=david@kernel.org; h=from:subject:message-id; bh=glmREPecf3Soxf23A8cAtJsaeHFT2ex5UzHoQI9g+28=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLKebk8TXHrRW3j5ImPXqRM2+EWeLvBgOzKltzWl/Yf1J /Wu2evmdpSyMIhxMMiKKbIEBd83ePlyXW21Gx8zzBxWJpAhDFycAjARpheMDFNaAhtDhL1kNO1c dGdue3/ixn6rTU5ud9Ss+l5+3C7szsbwk7Fgs0P+Td/7KsFuhndbzDKmPefPbc5Li/3Itfb6dNY p3AA= X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A X-Rspamd-Queue-Id: 156D5180004 X-Stat-Signature: wu6z3f5coscess7rpwhh1b1a6wq8fqif X-Rspamd-Server: rspam04 X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1793439755-610496 X-HE-Meta: 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 +XehCMd8 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 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 page_vma_mapped_walk() can return non-present device-exclusive entries, but folio_referenced_one() passes them to PTE young-bit accessors that require present PTEs. We must neither call clear_flush_young_ptes_notify() nor folio_pte_batch() with non-present entries. For example, clearing the young bit on non-present PTEs can corrupt the entry: on arm64 PTE_AF overlaps the swap type, so clearing it turns a device-exclusive entry into an ordinary swap entry. folio_pte_batch() will VM_WARN_ON_FOLIO. Apply the same approach as the previous fixes to e.g., damon_ptep_mkold(): treat these entries as old from the CPU's perspective and obtain their young state through the MMU notifier. Skip PTE batching and MGLRU look-around for non-present entries, and don't modify non-present PTEs. Fixes: b756a3b5e7ea ("mm: device exclusive memory access") Reviewed-by: Lorenzo Stoakes (ARM) Cc: stable@vger.kernel.org Reported-by: Josef Bacik Reviewed-by: Harry Yoo (Meta) Reviewed-by: Barry Song Reviewed-by: Dev Jain Tested-by: Muhammad Usama Anjum Signed-off-by: David Hildenbrand (Arm) --- mm/rmap.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 1131b76bbbc28..0faef46806e5c 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -924,6 +924,7 @@ static bool folio_referenced_one(struct folio *folio, DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, address, 0); int ptes = 0, referenced = 0; unsigned int nr; + pte_t pteval; while (page_vma_mapped_walk(&pvmw)) { address = pvmw.address; @@ -968,10 +969,12 @@ static bool folio_referenced_one(struct folio *folio, return false; } - if (pvmw.pte && folio_test_large(folio)) { + if (pvmw.pte) + pteval = ptep_get(pvmw.pte); + + if (pvmw.pte && pte_present(pteval) && folio_test_large(folio)) { const unsigned long end_addr = pmd_addr_end(address, vma->vm_end); const unsigned int max_nr = (end_addr - address) >> PAGE_SHIFT; - pte_t pteval = ptep_get(pvmw.pte); nr = folio_pte_batch(folio, pvmw.pte, pteval, max_nr); } @@ -981,11 +984,23 @@ static bool folio_referenced_one(struct folio *folio, * are. —they could be on active/inactive lists or on MGLRU. So the * simplest approach is to disable this look-around optimization. */ - if (lru_gen_enabled() && !lru_gen_switching() && pvmw.pte) { + if (lru_gen_enabled() && !lru_gen_switching() && pvmw.pte && + pte_present(pteval)) { if (lru_gen_look_around(&pvmw, nr)) referenced++; } else if (pvmw.pte) { - if (clear_flush_young_ptes_notify(vma, address, pvmw.pte, nr)) + bool young = false; + + /* + * PFN swap PTEs, such as device-exclusive ones, that + * actually map pages are "old" from a CPU perspective. + * The MMU notifier takes care of any device aspects. + */ + if (pte_present(pteval)) + young = clear_flush_young_ptes(vma, address, pvmw.pte, nr); + young |= mmu_notifier_clear_flush_young(vma->vm_mm, address, + address + nr * PAGE_SIZE); + if (young) referenced++; } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { if (pmdp_clear_flush_young_notify(vma, address, -- 2.43.0