From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4409CC7EE45 for ; Fri, 9 Jun 2023 20:11:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230327AbjFIULK (ORCPT ); Fri, 9 Jun 2023 16:11:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56824 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230357AbjFIULE (ORCPT ); Fri, 9 Jun 2023 16:11:04 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 544BF3A85 for ; Fri, 9 Jun 2023 13:11:03 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D828461E7E for ; Fri, 9 Jun 2023 20:11:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D89DC433D2; Fri, 9 Jun 2023 20:11:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1686341462; bh=PyqTUoOJFJqfVQtGZLEOop4msBX14t7ZH16CSongymA=; h=Date:To:From:Subject:From; b=N8FkSdE7jsSPyK+pwrsgrQGNNv3mcJ2uMKJJFHUp7BavzFGfLROjLjqk26R8Xhndi 92kJcjHSp5O1bEkRRGIR2DsUwLyYd1L7UrY96OItx3mW3N9VPHXevYvfAaphVSAMyu zGAzlAa92pg95LUuVBPxj6aoDgt2InIIgouCJjG4= Date: Fri, 09 Jun 2023 13:11:01 -0700 To: mm-commits@vger.kernel.org, zhengqi.arch@bytedance.com, zackr@vmware.com, yuzhao@google.com, ying.huang@intel.com, willy@infradead.org, will@kernel.org, thomas.hellstrom@linux.intel.com, surenb@google.com, steven.price@arm.com, song@kernel.org, sj@kernel.org, shy828301@gmail.com, ryan.roberts@arm.com, rppt@kernel.org, rcampbell@nvidia.com, peterz@infradead.org, peterx@redhat.com, pasha.tatashin@soleen.com, naoya.horiguchi@nec.com, minchan@kernel.org, mike.kravetz@oracle.com, mgorman@techsingularity.net, lstoakes@gmail.com, linmiaohe@huawei.com, kirill.shutemov@linux.intel.com, jgg@ziepe.ca, ira.weiny@intel.com, hch@infradead.org, david@redhat.com, christophe.leroy@csgroup.eu, axelrasmussen@google.com, apopple@nvidia.com, anshuman.khandual@arm.com, hughd@google.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-pagewalkers-action_again-if-pte_offset_map_lock-fails.patch added to mm-unstable branch Message-Id: <20230609201102.2D89DC433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/pagewalkers: ACTION_AGAIN if pte_offset_map_lock() fails has been added to the -mm mm-unstable branch. Its filename is mm-pagewalkers-action_again-if-pte_offset_map_lock-fails.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-pagewalkers-action_again-if-pte_offset_map_lock-fails.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Hugh Dickins Subject: mm/pagewalkers: ACTION_AGAIN if pte_offset_map_lock() fails Date: Thu, 8 Jun 2023 18:17:26 -0700 (PDT) Simple walk_page_range() users should set ACTION_AGAIN to retry when pte_offset_map_lock() fails. No need to check pmd_trans_unstable(): that was precisely to avoid the possiblity of calling pte_offset_map() on a racily removed or inserted THP entry, but such cases are now safely handled inside it. Likewise there is no need to check pmd_none() or pmd_bad() before calling it. Link: https://lkml.kernel.org/r/c77d9d10-3aad-e3ce-4896-99e91c7947f3@google.com Signed-off-by: Hugh Dickins Reviewed-by: SeongJae Park for mm/damon part Cc: Alistair Popple Cc: Anshuman Khandual Cc: Axel Rasmussen Cc: Christophe Leroy Cc: Christoph Hellwig Cc: David Hildenbrand Cc: "Huang, Ying" Cc: Ira Weiny Cc: Jason Gunthorpe Cc: Kirill A. Shutemov Cc: Lorenzo Stoakes Cc: Matthew Wilcox Cc: Mel Gorman Cc: Miaohe Lin Cc: Mike Kravetz Cc: Mike Rapoport (IBM) Cc: Minchan Kim Cc: Naoya Horiguchi Cc: Pavel Tatashin Cc: Peter Xu Cc: Peter Zijlstra Cc: Qi Zheng Cc: Ralph Campbell Cc: Ryan Roberts Cc: Song Liu Cc: Steven Price Cc: Suren Baghdasaryan Cc: Thomas Hellström Cc: Will Deacon Cc: Yang Shi Cc: Yu Zhao Cc: Zack Rusin Signed-off-by: Andrew Morton --- fs/proc/task_mmu.c | 32 ++++++++++++++++---------------- mm/damon/vaddr.c | 12 ++++++++---- mm/mempolicy.c | 7 ++++--- mm/mincore.c | 9 ++++----- mm/mlock.c | 4 ++++ 5 files changed, 36 insertions(+), 28 deletions(-) --- a/fs/proc/task_mmu.c~mm-pagewalkers-action_again-if-pte_offset_map_lock-fails +++ a/fs/proc/task_mmu.c @@ -631,14 +631,11 @@ static int smaps_pte_range(pmd_t *pmd, u goto out; } - if (pmd_trans_unstable(pmd)) - goto out; - /* - * The mmap_lock held all the way back in m_start() is what - * keeps khugepaged out of here and from collapsing things - * in here. - */ pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + if (!pte) { + walk->action = ACTION_AGAIN; + return 0; + } for (; addr != end; pte++, addr += PAGE_SIZE) smaps_pte_entry(pte, addr, walk); pte_unmap_unlock(pte - 1, ptl); @@ -1191,10 +1188,11 @@ out: return 0; } - if (pmd_trans_unstable(pmd)) - return 0; - pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + if (!pte) { + walk->action = ACTION_AGAIN; + return 0; + } for (; addr != end; pte++, addr += PAGE_SIZE) { ptent = *pte; @@ -1538,9 +1536,6 @@ static int pagemap_pmd_range(pmd_t *pmdp spin_unlock(ptl); return err; } - - if (pmd_trans_unstable(pmdp)) - return 0; #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ /* @@ -1548,6 +1543,10 @@ static int pagemap_pmd_range(pmd_t *pmdp * goes beyond vma->vm_end. */ orig_pte = pte = pte_offset_map_lock(walk->mm, pmdp, addr, &ptl); + if (!pte) { + walk->action = ACTION_AGAIN; + return err; + } for (; addr < end; pte++, addr += PAGE_SIZE) { pagemap_entry_t pme; @@ -1887,11 +1886,12 @@ static int gather_pte_stats(pmd_t *pmd, spin_unlock(ptl); return 0; } - - if (pmd_trans_unstable(pmd)) - return 0; #endif orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); + if (!pte) { + walk->action = ACTION_AGAIN; + return 0; + } do { struct page *page = can_gather_numa_stats(*pte, vma, addr); if (!page) --- a/mm/damon/vaddr.c~mm-pagewalkers-action_again-if-pte_offset_map_lock-fails +++ a/mm/damon/vaddr.c @@ -318,9 +318,11 @@ static int damon_mkold_pmd_entry(pmd_t * spin_unlock(ptl); } - if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) - return 0; pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); + if (!pte) { + walk->action = ACTION_AGAIN; + return 0; + } if (!pte_present(*pte)) goto out; damon_ptep_mkold(pte, walk->vma, addr); @@ -464,9 +466,11 @@ huge_out: regular_page: #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ - if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) - return -EINVAL; pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); + if (!pte) { + walk->action = ACTION_AGAIN; + return 0; + } if (!pte_present(*pte)) goto out; folio = damon_get_folio(pte_pfn(*pte)); --- a/mm/mempolicy.c~mm-pagewalkers-action_again-if-pte_offset_map_lock-fails +++ a/mm/mempolicy.c @@ -514,10 +514,11 @@ static int queue_folios_pte_range(pmd_t if (ptl) return queue_folios_pmd(pmd, ptl, addr, end, walk); - if (pmd_trans_unstable(pmd)) - return 0; - mapped_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); + if (!pte) { + walk->action = ACTION_AGAIN; + return 0; + } for (; addr != end; pte++, addr += PAGE_SIZE) { if (!pte_present(*pte)) continue; --- a/mm/mincore.c~mm-pagewalkers-action_again-if-pte_offset_map_lock-fails +++ a/mm/mincore.c @@ -113,12 +113,11 @@ static int mincore_pte_range(pmd_t *pmd, goto out; } - if (pmd_trans_unstable(pmd)) { - __mincore_unmapped_range(addr, end, vma, vec); - goto out; - } - ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); + if (!ptep) { + walk->action = ACTION_AGAIN; + return 0; + } for (; addr != end; ptep++, addr += PAGE_SIZE) { pte_t pte = *ptep; --- a/mm/mlock.c~mm-pagewalkers-action_again-if-pte_offset_map_lock-fails +++ a/mm/mlock.c @@ -329,6 +329,10 @@ static int mlock_pte_range(pmd_t *pmd, u } start_pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + if (!start_pte) { + walk->action = ACTION_AGAIN; + return 0; + } for (pte = start_pte; addr != end; pte++, addr += PAGE_SIZE) { if (!pte_present(*pte)) continue; _ Patches currently in -mm which might be from hughd@google.com are arm-allow-pte_offset_map-to-fail.patch arm64-allow-pte_offset_map-to-fail.patch arm64-hugetlb-pte_alloc_huge-pte_offset_huge.patch ia64-hugetlb-pte_alloc_huge-pte_offset_huge.patch m68k-allow-pte_offset_map-to-fail.patch microblaze-allow-pte_offset_map-to-fail.patch mips-update_mmu_cache-can-replace-__update_tlb.patch mips-update_mmu_cache-can-replace-__update_tlb-fix.patch parisc-add-pte_unmap-to-balance-get_ptep.patch parisc-unmap_uncached_pte-use-pte_offset_kernel.patch parisc-hugetlb-pte_alloc_huge-pte_offset_huge.patch powerpc-kvmppc_unmap_free_pmd-pte_offset_kernel.patch powerpc-allow-pte_offset_map-to-fail.patch powerpc-hugetlb-pte_alloc_huge.patch riscv-hugetlb-pte_alloc_huge-pte_offset_huge.patch s390-allow-pte_offset_map_lock-to-fail.patch s390-gmap-use-pte_unmap_unlock-not-spin_unlock.patch sh-hugetlb-pte_alloc_huge-pte_offset_huge.patch sparc-hugetlb-pte_alloc_huge-pte_offset_huge.patch sparc-allow-pte_offset_map-to-fail.patch sparc-iounit-and-iommu-use-pte_offset_kernel.patch x86-allow-get_locked_pte-to-fail.patch x86-sme_populate_pgd-use-pte_offset_kernel.patch xtensa-add-pte_unmap-to-balance-pte_offset_map.patch mm-use-pmdp_get_lockless-without-surplus-barrier.patch mm-migrate-remove-cruft-from-migration_entry_waits.patch mm-pgtable-kmap_local_page-instead-of-kmap_atomic.patch mm-pgtable-allow-pte_offset_map-to-fail.patch mm-filemap-allow-pte_offset_map_lock-to-fail.patch mm-page_vma_mapped-delete-bogosity-in-page_vma_mapped_walk.patch mm-page_vma_mapped-reformat-map_pte-with-less-indentation.patch mm-page_vma_mapped-pte_offset_map_nolock-not-pte_lockptr.patch mm-pagewalkers-action_again-if-pte_offset_map_lock-fails.patch mm-pagewalk-walk_pte_range-allow-for-pte_offset_map.patch mm-vmwgfx-simplify-pmd-pud-mapping-dirty-helpers.patch mm-vmalloc-vmalloc_to_page-use-pte_offset_kernel.patch mm-hmm-retry-if-pte_offset_map-fails.patch mm-userfaultfd-retry-if-pte_offset_map-fails.patch mm-userfaultfd-allow-pte_offset_map_lock-to-fail.patch mm-debug_vm_pgtablepage_table_check-warn-pte-map-fails.patch mm-various-give-up-if-pte_offset_map-fails.patch mm-mprotect-delete-pmd_none_or_clear_bad_unless_trans_huge.patch mm-mremap-retry-if-either-pte_offset_map_lock-fails.patch mm-madvise-clean-up-pte_offset_map_lock-scans.patch mm-madvise-clean-up-force_shm_swapin_readahead.patch mm-swapoff-allow-pte_offset_map-to-fail.patch mm-mglru-allow-pte_offset_map_nolock-to-fail.patch mm-migrate_device-allow-pte_offset_map_lock-to-fail.patch mm-gup-remove-foll_split_pmd-use-of-pmd_trans_unstable.patch mm-huge_memory-split-huge-pmd-under-one-pte_offset_map.patch mm-khugepaged-allow-pte_offset_map-to-fail.patch mm-memory-allow-pte_offset_map-to-fail.patch mm-memory-handle_pte_fault-use-pte_offset_map_nolock.patch mm-pgtable-delete-pmd_trans_unstable-and-friends.patch mm-swap-swap_vma_readahead-do-the-pte_offset_map.patch perf-core-allow-pte_offset_map-to-fail.patch