From patchwork Thu Feb 16 05:17:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suren Baghdasaryan X-Patchwork-Id: 57852 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:eb09:0:0:0:0:0 with SMTP id s9csp117142wrn; Wed, 15 Feb 2023 21:20:40 -0800 (PST) X-Google-Smtp-Source: AK7set/fGhMbSwNCCdFjFx4PBhHUII0DhV8RoOryp5VLxFsU+2Ntg/pNs1ZhXeCZoCoss7a8ba7z X-Received: by 2002:a50:ec97:0:b0:4ac:bbb1:e61c with SMTP id e23-20020a50ec97000000b004acbbb1e61cmr4560101edr.1.1676524839994; Wed, 15 Feb 2023 21:20:39 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1676524839; cv=none; d=google.com; s=arc-20160816; b=keErRDpSz5PWMOmunyqjT4Vf+KitqX6xI+TmWYslO8jlyFF5RMlPbXLEptEynB2/Cf sn2c4PLxZg1Pw33ICU1GcaemH1frl7uK0p89ewFeB3xVbYDq4hfMy6yPBzv1uQHxMxmg KnlrQ52E71LNQybiCeMmWwMwB0yd6Vct7hjSowdKg8rA84VhhKOZB15+hjpU1iSXGr5b LIELZbkESQ8z6tQPihgaQXKQ+jg5Bwwma5uMNE11i9f2tq4DP+JcIiDk84NwMy1DalvN ZDN+mZo6Z87V5Tut8YC+eP2MOOOjBNAq6nTN56EED4Frndo/0tcIm+5pU4ZzXl7zEtr+ BqIA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:dkim-signature; bh=4tPY63bpwhpT+tcOBCZmVWQ4EsQSsAiOumfwemoUSR4=; b=Am3o0haW5e3vZx8x39pI5GJr3RKemViqVKTRH4aR5Hk9AFIgtZHvhMXajUGLl0tTJH lmofaCp7MZnkypBU47I1CPBOZxzEJciLIbuLKihQfoQicLd9IE7j4pcK55I0wD6jbGlU w4ocjCkIfvs387cWgRDbekKcKsmbBpiS4CaAyjkJ7g5wLd0Sv9OoFQSzfTGxwbQhUXJx 8MdKKPNmFpi/lATBEx8vmOHXrBXWJvV3HIwxkX5zHryJ1xhO2T7NwnlpF9Oxs7s8vY9C HxpWpgUoUUk7zBza9G3F3mybEzc58gHUVWbANhcvkow7ceUaCIyOQoAtLbWqC+VA3X/6 A6xg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b=S2sXkiCN; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id d12-20020a056402078c00b004acb37caea9si993644edy.344.2023.02.15.21.20.16; Wed, 15 Feb 2023 21:20:39 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b=S2sXkiCN; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229687AbjBPFT6 (ORCPT + 99 others); Thu, 16 Feb 2023 00:19:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46884 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229736AbjBPFTQ (ORCPT ); Thu, 16 Feb 2023 00:19:16 -0500 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0B0947416 for ; Wed, 15 Feb 2023 21:18:36 -0800 (PST) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-52ec8c88d75so8524207b3.12 for ; Wed, 15 Feb 2023 21:18:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=4tPY63bpwhpT+tcOBCZmVWQ4EsQSsAiOumfwemoUSR4=; b=S2sXkiCN7LWOjXaeaMYvz0qNJtP37xcl3aD2Yh+x1ZEOEg3KLdTaCbat1bdYvpjsne ssUpFmsgMZn2ZzaQIQ1nCUMhum1BKo1kVXXpN4w0/hSPSa2H/9hW6SiJ4urWGDrWEDIg /lDLOzKc/0bGJk2Y7O7P1pt9zjSY2dn9UPLftjGBDJCogvybLOdBJ/pVV0l/nLyc8nbd 78hCVT3xeGJZ3GfClpuKXysNAZLItz5CqeYcRfuccmKUwUq5LhC6V5ar511CeqKShlzR g15CQtYg8YR8Te7+dSB+30LV6maBKvWp8iWZepEStLZa94uN9djYv3KGIMR2EUqABQ+Q /xVA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=4tPY63bpwhpT+tcOBCZmVWQ4EsQSsAiOumfwemoUSR4=; b=1gSp1NhqKDSGVwAYOrs7UiLEtJSXs/IZIItXO+LeS/aSR5jAeqWBV1BD8ll43L61ZD 2mJyESaOQrLAJg7LYujyxfmj8o0Es8EkyaJp8/VAaOE2uU0Zqu5sZyK9PPtqpC0jN78+ KrJLQm1k4oN13qGwlatE4W30dlmUkhQEeRuW2Eqy/B758r7v0nYScKo0RgwoMh5yvTQa idQg6T4r/A6qXoFuY4oLsJ3ZYVY/L+EzAsMvfr0JuYRG7Rv+AaaESpKMvF5+VSL1khRl m8c40SwUTXYvTwvsgTnd51eQ/2Ce/XC1V6tNSlWAQGnJB+8aV0GI+B6WdVB5pJadWK25 /EEw== X-Gm-Message-State: AO0yUKVO2ispUTM5pBxHy2HkofDvcWn6bm6Ec5DczVN9HbhBMrK86TIj 4qgRcRIGlTKDLXQoQ0ooXPuLJ1WvOUA= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:200:f781:d5ed:1806:6ebb]) (user=surenb job=sendgmr) by 2002:a05:6902:10f:b0:855:fa17:4f5f with SMTP id o15-20020a056902010f00b00855fa174f5fmr82ybh.1.1676524711465; Wed, 15 Feb 2023 21:18:31 -0800 (PST) Date: Wed, 15 Feb 2023 21:17:30 -0800 In-Reply-To: <20230216051750.3125598-1-surenb@google.com> Mime-Version: 1.0 References: <20230216051750.3125598-1-surenb@google.com> X-Mailer: git-send-email 2.39.1.581.gbfd45094c4-goog Message-ID: <20230216051750.3125598-16-surenb@google.com> Subject: [PATCH v3 15/35] mm/khugepaged: write-lock VMA while collapsing a huge page From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, paulmck@kernel.org, mingo@redhat.com, will@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, chriscli@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, rppt@kernel.org, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, leewalsh@google.com, posk@google.com, michalechner92@googlemail.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com, Suren Baghdasaryan X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1757963710804216537?= X-GMAIL-MSGID: =?utf-8?q?1757963710804216537?= Protect VMA from concurrent page fault handler while collapsing a huge page. Page fault handler needs a stable PMD to use PTL and relies on per-VMA lock to prevent concurrent PMD changes. pmdp_collapse_flush(), set_huge_pmd() and collapse_and_free_pmd() can modify a PMD, which will not be detected by a page fault handler without proper locking. Before this patch, page tables can be walked under any one of the mmap_lock, the mapping lock, and the anon_vma lock; so when khugepaged unlinks and frees page tables, it must ensure that all of those either are locked or don't exist. This patch adds a fourth lock under which page tables can be traversed, and so khugepaged must also lock out that one. Signed-off-by: Suren Baghdasaryan --- mm/khugepaged.c | 5 +++++ mm/rmap.c | 31 ++++++++++++++++--------------- 2 files changed, 21 insertions(+), 15 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 8dbc39896811..d9376acf1fbe 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1140,6 +1140,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address, if (result != SCAN_SUCCEED) goto out_up_write; + vma_start_write(vma); anon_vma_lock_write(vma->anon_vma); mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, address, @@ -1607,6 +1608,9 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr, goto drop_hpage; } + /* Lock the vma before taking i_mmap and page table locks */ + vma_start_write(vma); + /* * We need to lock the mapping so that from here on, only GUP-fast and * hardware page walks can access the parts of the page tables that @@ -1812,6 +1816,7 @@ static int retract_page_tables(struct address_space *mapping, pgoff_t pgoff, result = SCAN_PTE_UFFD_WP; goto unlock_next; } + vma_start_write(vma); collapse_and_free_pmd(mm, vma, addr, pmd); if (!cc->is_khugepaged && is_target) result = set_huge_pmd(vma, addr, pmd, hpage); diff --git a/mm/rmap.c b/mm/rmap.c index 15ae24585fc4..8e1a2ad9ca53 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -25,21 +25,22 @@ * mapping->invalidate_lock (in filemap_fault) * page->flags PG_locked (lock_page) * hugetlbfs_i_mmap_rwsem_key (in huge_pmd_share, see hugetlbfs below) - * mapping->i_mmap_rwsem - * anon_vma->rwsem - * mm->page_table_lock or pte_lock - * swap_lock (in swap_duplicate, swap_info_get) - * mmlist_lock (in mmput, drain_mmlist and others) - * mapping->private_lock (in block_dirty_folio) - * folio_lock_memcg move_lock (in block_dirty_folio) - * i_pages lock (widely used) - * lruvec->lru_lock (in folio_lruvec_lock_irq) - * inode->i_lock (in set_page_dirty's __mark_inode_dirty) - * bdi.wb->list_lock (in set_page_dirty's __mark_inode_dirty) - * sb_lock (within inode_lock in fs/fs-writeback.c) - * i_pages lock (widely used, in set_page_dirty, - * in arch-dependent flush_dcache_mmap_lock, - * within bdi.wb->list_lock in __sync_single_inode) + * vma_start_write + * mapping->i_mmap_rwsem + * anon_vma->rwsem + * mm->page_table_lock or pte_lock + * swap_lock (in swap_duplicate, swap_info_get) + * mmlist_lock (in mmput, drain_mmlist and others) + * mapping->private_lock (in block_dirty_folio) + * folio_lock_memcg move_lock (in block_dirty_folio) + * i_pages lock (widely used) + * lruvec->lru_lock (in folio_lruvec_lock_irq) + * inode->i_lock (in set_page_dirty's __mark_inode_dirty) + * bdi.wb->list_lock (in set_page_dirty's __mark_inode_dirty) + * sb_lock (within inode_lock in fs/fs-writeback.c) + * i_pages lock (widely used, in set_page_dirty, + * in arch-dependent flush_dcache_mmap_lock, + * within bdi.wb->list_lock in __sync_single_inode) * * anon_vma->rwsem,mapping->i_mmap_rwsem (memory_failure, collect_procs_anon) * ->tasklist_lock