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 1F564C433F5 for ; Sun, 24 Apr 2022 20:03:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239524AbiDXUGR (ORCPT ); Sun, 24 Apr 2022 16:06:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232795AbiDXUGR (ORCPT ); Sun, 24 Apr 2022 16:06:17 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C6E891EAD0 for ; Sun, 24 Apr 2022 13:03:15 -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 428D061314 for ; Sun, 24 Apr 2022 20:03:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 87F18C385AB; Sun, 24 Apr 2022 20:03:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1650830594; bh=9Op8Yuq82mSl/Fe/dwyf32pynWmLY/x/fpcRGVXk1r0=; h=Date:To:From:Subject:From; b=cLuJS649tsXeIzByWIN9yMWSgyzfiD3CLnselLH5j38minkA2zGiXfC+t8BN8Qefl LIsGL0CLf+tOizTYZs9Tqqf/afGwKoJHi3MDz6q6UKi3/ooLfOjJ7qgVZ/lk+cC3nb R6ccjunquRGkYigJfRtB3JZ6mbaAq/BMtbzzAftk= Date: Sun, 24 Apr 2022 13:03:13 -0700 To: mm-commits@vger.kernel.org, willy@infradead.org, vbabka@suse.cz, surenb@google.com, sfr@canb.auug.org.au, peterx@redhat.com, neilb@suse.de, naoya.horiguchi@nec.com, minchan@kernel.org, dhowells@redhat.com, david@redhat.com, apopple@nvidia.com, linmiaohe@huawei.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-swapfile-unuse_pte-can-map-random-data-if-swap-read-fails.patch added to -mm tree Message-Id: <20220424200314.87F18C385AB@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/swapfile: unuse_pte can map random data if swap read fails has been added to the -mm tree. Its filename is mm-swapfile-unuse_pte-can-map-random-data-if-swap-read-fails.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-swapfile-unuse_pte-can-map-random-data-if-swap-read-fails.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-swapfile-unuse_pte-can-map-random-data-if-swap-read-fails.patch 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Miaohe Lin Subject: mm/swapfile: unuse_pte can map random data if swap read fails There is a bug in unuse_pte(): when swap page happens to be unreadable, page filled with random data is mapped into user address space. In case of error, a special swap entry indicating swap read fails is set to the page table. So the swapcache page can be freed and the user won't end up with a permanently mounted swap because a sector is bad. And if the page is accessed later, the user process will be killed so that corrupted data is never consumed. On the other hand, if the page is never accessed, the user won't even notice it. Link: https://lkml.kernel.org/r/20220424091105.48374-2-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Acked-by: David Hildenbrand Cc: Peter Xu Cc: Alistair Popple Cc: David Howells Cc: Matthew Wilcox Cc: Minchan Kim Cc: Naoya Horiguchi Cc: NeilBrown Cc: Stephen Rothwell Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- include/linux/swap.h | 7 ++++++- include/linux/swapops.h | 10 ++++++++++ mm/memory.c | 5 ++++- mm/swapfile.c | 11 +++++++++++ 4 files changed, 31 insertions(+), 2 deletions(-) --- a/include/linux/swap.h~mm-swapfile-unuse_pte-can-map-random-data-if-swap-read-fails +++ a/include/linux/swap.h @@ -55,6 +55,10 @@ static inline int current_is_kswapd(void * actions on faults. */ +#define SWP_SWAPIN_ERROR_NUM 1 +#define SWP_SWAPIN_ERROR (MAX_SWAPFILES + SWP_HWPOISON_NUM + \ + SWP_MIGRATION_NUM + SWP_DEVICE_NUM + \ + SWP_PTE_MARKER_NUM) /* * PTE markers are used to persist information onto PTEs that are mapped with * file-backed memories. As its name "PTE" hints, it should only be applied to @@ -120,7 +124,8 @@ static inline int current_is_kswapd(void #define MAX_SWAPFILES \ ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \ - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM - SWP_PTE_MARKER_NUM) + SWP_MIGRATION_NUM - SWP_HWPOISON_NUM - \ + SWP_PTE_MARKER_NUM - SWP_SWAPIN_ERROR_NUM) /* * Magic header for a swap area. The first part of the union is --- a/include/linux/swapops.h~mm-swapfile-unuse_pte-can-map-random-data-if-swap-read-fails +++ a/include/linux/swapops.h @@ -108,6 +108,16 @@ static inline void *swp_to_radix_entry(s return xa_mk_value(entry.val); } +static inline swp_entry_t make_swapin_error_entry(struct page *page) +{ + return swp_entry(SWP_SWAPIN_ERROR, page_to_pfn(page)); +} + +static inline int is_swapin_error_entry(swp_entry_t entry) +{ + return swp_type(entry) == SWP_SWAPIN_ERROR; +} + #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset) { --- a/mm/memory.c~mm-swapfile-unuse_pte-can-map-random-data-if-swap-read-fails +++ a/mm/memory.c @@ -1488,7 +1488,8 @@ again: /* Only drop the uffd-wp marker if explicitly requested */ if (!zap_drop_file_uffd_wp(details)) continue; - } else if (is_hwpoison_entry(entry)) { + } else if (is_hwpoison_entry(entry) || + is_swapin_error_entry(entry)) { if (!should_zap_cows(details)) continue; } else { @@ -3728,6 +3729,8 @@ vm_fault_t do_swap_page(struct vm_fault ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); } else if (is_hwpoison_entry(entry)) { ret = VM_FAULT_HWPOISON; + } else if (is_swapin_error_entry(entry)) { + ret = VM_FAULT_SIGBUS; } else if (is_pte_marker_entry(entry)) { ret = handle_pte_marker(vmf); } else { --- a/mm/swapfile.c~mm-swapfile-unuse_pte-can-map-random-data-if-swap-read-fails +++ a/mm/swapfile.c @@ -1797,6 +1797,17 @@ static int unuse_pte(struct vm_area_stru goto out; } + if (unlikely(!PageUptodate(page))) { + pte_t pteval; + + dec_mm_counter(vma->vm_mm, MM_SWAPENTS); + pteval = swp_entry_to_pte(make_swapin_error_entry(page)); + set_pte_at(vma->vm_mm, addr, pte, pteval); + swap_free(entry); + ret = 0; + goto out; + } + /* See do_swap_page() */ BUG_ON(!PageAnon(page) && PageMappedToDisk(page)); BUG_ON(PageAnon(page) && PageAnonExclusive(page)); _ Patches currently in -mm which might be from linmiaohe@huawei.com are mm-shmem-make-shmem_init-return-void.patch mm-memcg-remove-unneeded-nr_scanned.patch mm-mmapc-use-helper-mlock_future_check.patch mm-mremap-use-helper-mlock_future_check.patch mm-mremap-avoid-unneeded-do_munmap-call.patch mm-memory-failurec-minor-cleanup-for-hwpoisonhandlable.patch mm-memory-failurec-dissolve-truncated-hugetlb-page.patch mm-vmscan-remove-obsolete-comment-in-get_scan_count.patch mm-vmscan-fix-comment-for-current_may_throttle.patch mm-vmscan-fix-comment-for-isolate_lru_pages.patch mm-z3fold-declare-z3fold_mount-with-__init.patch mm-z3fold-remove-obsolete-comment-in-z3fold_alloc.patch mm-z3fold-minor-clean-up-for-z3fold_free.patch mm-z3fold-remove-unneeded-page_mapcount_reset-and-clearpageprivate.patch mm-z3fold-remove-confusing-local-variable-l-reassignment.patch mm-z3fold-move-decrement-of-pool-pages_nr-into-__release_z3fold_page.patch mm-z3fold-remove-redundant-list_del_init-of-zhdr-buddy-in-z3fold_free.patch mm-z3fold-remove-unneeded-page_headless-check-in-free_handle.patch mm-compaction-use-helper-isolation_suitable.patch drivers-base-nodec-fix-compaction-sysfs-file-leak.patch mm-mempolicy-clean-up-the-code-logic-in-queue_pages_pte_range.patch mm-migration-remove-unneeded-local-variable-mapping_locked.patch mm-migration-remove-unneeded-local-variable-page_lru.patch mm-migration-use-helper-function-vma_lookup-in-add_page_for_migration.patch mm-migration-use-helper-macro-min-in-do_pages_stat.patch mm-migration-avoid-unneeded-nodemask_t-initialization.patch mm-migration-remove-some-duplicated-codes-in-migrate_pages.patch mm-migration-fix-potential-page-refcounts-leak-in-migrate_pages.patch mm-migration-fix-potential-invalid-node-access-for-reclaim-based-migration.patch mm-migration-fix-possible-do_pages_stat_array-racing-with-memory-offline.patch mm-madvise-fix-potential-pte_unmap_unlock-pte-error.patch mm-madvise-free-hwpoison-and-swapin-error-entry-in-madvise_free_pte_range.patch mm-compaction-remove-unneeded-return-value-of-kcompactd_run.patch mm-compaction-remove-unneeded-pfn-update.patch mm-compaction-remove-unneeded-assignment-to-isolate_start_pfn.patch mm-compaction-clean-up-comment-for-sched-contention.patch mm-compaction-clean-up-comment-about-suitable-migration-target-recheck.patch mm-compaction-use-compact_cluster_max-in-compactionc.patch mm-compaction-use-helper-compound_nr-in-isolate_migratepages_block.patch mm-compaction-clean-up-comment-about-async-compaction-in-isolate_migratepages.patch mm-compaction-avoid-possible-null-pointer-dereference-in-kcompactd_cpu_online.patch mm-compaction-make-compaction_zonelist_suitable-return-false-when-compact_success.patch mm-compaction-simplify-the-code-in-__compact_finished.patch mm-compaction-make-sure-highest-is-above-the-min_pfn.patch mm-swapfile-unuse_pte-can-map-random-data-if-swap-read-fails.patch mm-swapfile-fix-lost-swap-bits-in-unuse_pte.patch