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 BB0F0C43334 for ; Sat, 11 Jun 2022 22:03:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232370AbiFKWDm (ORCPT ); Sat, 11 Jun 2022 18:03:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42860 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230382AbiFKWDl (ORCPT ); Sat, 11 Jun 2022 18:03:41 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BFBEC109C for ; Sat, 11 Jun 2022 15:03:39 -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 ams.source.kernel.org (Postfix) with ESMTPS id 8A032B80B4D for ; Sat, 11 Jun 2022 22:03:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 32009C34116; Sat, 11 Jun 2022 22:03:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1654985017; bh=4LcIvE4JHImDyiTc4UKCKw+JA/J93lw/s3zA9KtcJaU=; h=Date:To:From:Subject:From; b=Z5my698AP7LA9sIuCzRJmtUJsYjiqwKtIng3AIBP8cO5cCX+gM+batBEQeV1BeM/S gB0yH9Ip5K0DRFEh0pklrSbOwps/icSmbJlkeQiUi3YKk5rZ5Dyo5zfhir5oJ12fiv IGOJE3t2ARnbrKYdfmjs0U3OX5F/af3U80V3wgkI= Date: Sat, 11 Jun 2022 15:03:36 -0700 To: mm-commits@vger.kernel.org, hughd@google.com, david@redhat.com, linmiaohe@huawei.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-swapfile-make-security_vm_enough_memory_mm-work-as-expected.patch added to mm-unstable branch Message-Id: <20220611220337.32009C34116@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: make security_vm_enough_memory_mm() work as expected has been added to the -mm mm-unstable branch. Its filename is mm-swapfile-make-security_vm_enough_memory_mm-work-as-expected.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-swapfile-make-security_vm_enough_memory_mm-work-as-expected.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: Miaohe Lin Subject: mm/swapfile: make security_vm_enough_memory_mm() work as expected Date: Wed, 8 Jun 2022 22:40:29 +0800 Patch series "A few cleanup and fixup patches for swap", v2. This series contains a cleaup patch to remove unneeded swap_cache_info statistics, and two bugfix patches to avoid possible data races of inuse_pages and so on. More details can be found in the respective changelogs. This patch (of 3): security_vm_enough_memory_mm() checks whether a process has enough memory to allocate a new virtual mapping. And total_swap_pages is considered as available memory while swapoff tries to make sure there's enough memory that can hold the swapped out memory. But total_swap_pages contains the swap space that is being swapoff. So security_vm_enough_memory_mm() will success even if there's no memory to hold the swapped out memory because total_swap_pages always greater than or equal to p->pages. In order to fix it, p->pages should be subtracted from total_swap_pages first and then check whether there's enough memory for inuse swap pages. Link: https://lkml.kernel.org/r/20220608144031.829-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20220608144031.829-2-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Cc: Hugh Dickins Cc: David Hildenbrand Signed-off-by: Andrew Morton --- mm/swapfile.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/mm/swapfile.c~mm-swapfile-make-security_vm_enough_memory_mm-work-as-expected +++ a/mm/swapfile.c @@ -2398,6 +2398,7 @@ SYSCALL_DEFINE1(swapoff, const char __us struct filename *pathname; int err, found = 0; unsigned int old_block_size; + unsigned int inuse_pages; if (!capable(CAP_SYS_ADMIN)) return -EPERM; @@ -2428,9 +2429,13 @@ SYSCALL_DEFINE1(swapoff, const char __us spin_unlock(&swap_lock); goto out_dput; } - if (!security_vm_enough_memory_mm(current->mm, p->pages)) - vm_unacct_memory(p->pages); + + total_swap_pages -= p->pages; + inuse_pages = READ_ONCE(p->inuse_pages); + if (!security_vm_enough_memory_mm(current->mm, inuse_pages)) + vm_unacct_memory(inuse_pages); else { + total_swap_pages += p->pages; err = -ENOMEM; spin_unlock(&swap_lock); goto out_dput; @@ -2453,7 +2458,6 @@ SYSCALL_DEFINE1(swapoff, const char __us } plist_del(&p->list, &swap_active_head); atomic_long_sub(p->pages, &nr_swap_pages); - total_swap_pages -= p->pages; p->flags &= ~SWP_WRITEOK; spin_unlock(&p->lock); spin_unlock(&swap_lock); _ Patches currently in -mm which might be from linmiaohe@huawei.com are maintainers-add-myself-as-a-memory-failure-reviewer.patch mm-shmemc-clean-up-comment-of-shmem_swapin_folio.patch mm-reduce-the-rcu-lock-duration.patch mm-migration-remove-unneeded-lock-page-and-pagemovable-check.patch mm-migration-return-errno-when-isolate_huge_page-failed.patch mm-migration-fix-potential-pte_unmap-on-an-not-mapped-pte.patch mm-memremap-fix-wrong-function-name-above-memremap_pages.patch mm-swapfile-make-security_vm_enough_memory_mm-work-as-expected.patch mm-swapfile-fix-possible-data-races-of-inuse_pages.patch mm-swap-remove-swap_cache_info-statistics.patch mm-vmscan-dont-try-to-reclaim-freed-folios.patch lib-test_hmm-avoid-accessing-uninitialized-pages.patch mm-memremap-fix-memunmap_pages-race-with-get_dev_pagemap.patch mm-khugepaged-remove-unneeded-shmem_huge_enabled-check.patch mm-khugepaged-stop-swapping-in-page-when-vm_fault_retry-occurs.patch mm-khugepaged-trivial-typo-and-codestyle-cleanup.patch mm-khugepaged-minor-cleanup-for-collapse_file.patch mm-khugepaged-use-helper-macro-__attr_rw.patch mm-khugepaged-remove-unneeded-return-value-of-khugepaged_add_pte_mapped_thp.patch mm-khugepaged-try-to-free-transhuge-swapcache-when-possible.patch mm-page_alloc-minor-clean-up-for-memmap_init_compound.patch