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INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1793342789-582016 X-HE-Meta: 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 jqwr1NKZ 0tXfrwRY0Sud0spWkBXDeFHWlATYMa3AMm09nGMkwXrgyo4dIlDpJIWPgiPRUt4KDhvj9ikHyVZgG/VOUALLApojofOl/de7E97hN2KgZK2i09wxGlNm766UtXy8BrjFAJIDnuDesMsst8ZrJGJNLjYzU+Hd1YdTJem4DRA8pPbtZX+W8gsCFKANgVsy3rA1VV5xxnvzKnFjRNl49EhCATXkVTFz35VEWZvza8mB7p0pC5cK/vElsNgPg10Za0Pb+xuD/yUSmj1bVk8a0K8TlERPMQzeprDFH1dCPjp6xhkndA9luWLegPkCKs+35l7tW+JcGZFSi8pw/8c/jgOXEOSxP4ggJAVts+tWW4x/rJ0HGOjtflXmHJ6RasTDLN3HzaEErnpPwLOklGcJpinrb1jdKL3P1ZmqYr2coaWj/kjROlX+Gtk09uCwtPQ== 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 2026-10-30 05:37, Ritesh Harjani (IBM) wrote: > Unmapping a device-dax mapping with 1G alignment on powerpc radix > kernel > built with CONFIG_DEBUG_VM triggers this warning on every munmap: > > WARNING: mm/mmu_gather.c:176 at > __tlb_remove_folio_pages_size+0x38/0x230 > NIP [c00000000063d508] __tlb_remove_folio_pages_size+0x38/0x230 > LR [c0000000006fb688] zap_huge_pud+0x1b8/0x2d0 > Call Trace: > zap_huge_pud+0x170/0x2d0 (unreliable) > __zap_vma_range+0x1604/0x1e20 > unmap_vmas+0xa0/0x1f0 > unmap_region+0xb0/0x130 > vms_complete_munmap_vmas+0x120/0x310 > do_vmi_align_munmap+0x1ec/0x240 > __vm_munmap+0x148/0x220 > sys_munmap+0x28/0x40 > > To trigger this - it is enough to mmap() /dev/dax0.0, touch the first > byte so that the whole 1G is mapped by a single PUD and then munmap() > it. > > PowerPC needs MMU_GATHER_PAGE_SIZE in which mmu_gather needs to record > the page size for which tlb flush is needed. zap_huge_pmd(), > zap_pte_range(), change_huge_pud() etc all do this already. However, > since commit: > dbe54153296d ("mm/huge_memory: add vmf_insert_folio_pud()") > > a device-dax PUD maps a real folio and zap_huge_pud() now hands it to > tlb_remove_page_size(tlb, page, HPAGE_PUD_SIZE). At that point > tlb->page_size is still whatever the previous user left behind, which > is > 0 for the fresh gather set up by munmap() and so the check fires. > > Fix this in the same way like how other similar paths do. > > Fixes: dbe54153296d0 ("mm/huge_memory: add vmf_insert_folio_pud()") > Reported-by: Pavithra > Signed-off-by: Ritesh Harjani (IBM) > --- > [v1]->v2: > ========= > - Split the 2 part patch series. Patch-1 is now superseded by a > different patch > from Muchun which he already posted [2]. > - No difference in this patch from v1. > > [v1]: > https://lore.kernel.org/all/97f85592bb78a273be8519e6897e7f9b9bd31469.1793070429.git.ritesh.list@gmail.com/ > [2]: > https://lore.kernel.org/all/20261029063601.1961415-1-songmuchun@bytedance.com/ > > mm/huge_memory.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index bd44d58e8684..7e589a2fb02d 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -3040,6 +3040,8 @@ int zap_huge_pud(struct mmu_gather *tlb, struct > vm_area_struct *vma, > spinlock_t *ptl; > pud_t orig_pud; > > + tlb_change_page_size(tlb, HPAGE_PUD_SIZE); > + > ptl = __pud_trans_huge_lock(pud, vma); > if (!ptl) > return 0; > -- > 2.39.5 Tested on Power10 (ppc64le), kernel v7.3 Tested-by: Pavithra Prakash