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 43E0CC433EF for ; Mon, 30 May 2022 11:30:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235847AbiE3Lah (ORCPT ); Mon, 30 May 2022 07:30:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235800AbiE3LaM (ORCPT ); Mon, 30 May 2022 07:30:12 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 206127E1FC for ; Mon, 30 May 2022 04:30:11 -0700 (PDT) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4LBY7h0cYBzgYTP; Mon, 30 May 2022 19:28:32 +0800 (CST) Received: from huawei.com (10.175.124.27) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 30 May 2022 19:30:08 +0800 From: Miaohe Lin To: , CC: , , , , , , , , , , , Subject: [PATCH v4 4/4] mm/migration: fix potential pte_unmap on an not mapped pte Date: Mon, 30 May 2022 19:30:16 +0800 Message-ID: <20220530113016.16663-5-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220530113016.16663-1-linmiaohe@huawei.com> References: <20220530113016.16663-1-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org __migration_entry_wait and migration_entry_wait_on_locked assume pte is always mapped from caller. But this is not the case when it's called from migration_entry_wait_huge and follow_huge_pmd. Add a hugetlbfs variant that calls hugetlb_migration_entry_wait(ptep == NULL) to fix this issue. Fixes: 30dad30922cc ("mm: migration: add migrate_entry_wait_huge()") Suggested-by: David Hildenbrand Signed-off-by: Miaohe Lin Reviewed-by: David Hildenbrand --- include/linux/swapops.h | 12 ++++++++---- mm/hugetlb.c | 4 ++-- mm/migrate.c | 23 +++++++++++++++++++---- 3 files changed, 29 insertions(+), 10 deletions(-) diff --git a/include/linux/swapops.h b/include/linux/swapops.h index f24775b41880..bb7afd03a324 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -244,8 +244,10 @@ extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, spinlock_t *ptl); extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, unsigned long address); -extern void migration_entry_wait_huge(struct vm_area_struct *vma, - struct mm_struct *mm, pte_t *pte); +#ifdef CONFIG_HUGETLB_PAGE +extern void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl); +extern void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte); +#endif #else static inline swp_entry_t make_readable_migration_entry(pgoff_t offset) { @@ -271,8 +273,10 @@ static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, spinlock_t *ptl) { } static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, unsigned long address) { } -static inline void migration_entry_wait_huge(struct vm_area_struct *vma, - struct mm_struct *mm, pte_t *pte) { } +#ifdef CONFIG_HUGETLB_PAGE +static inline void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl) { } +static inline void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte) { } +#endif static inline int is_writable_migration_entry(swp_entry_t entry) { return 0; diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 65ab215b39ee..c092157b896a 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5694,7 +5694,7 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, */ entry = huge_ptep_get(ptep); if (unlikely(is_hugetlb_entry_migration(entry))) { - migration_entry_wait_huge(vma, mm, ptep); + migration_entry_wait_huge(vma, ptep); return 0; } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) return VM_FAULT_HWPOISON_LARGE | @@ -6919,7 +6919,7 @@ follow_huge_pmd(struct mm_struct *mm, unsigned long address, } else { if (is_hugetlb_entry_migration(pte)) { spin_unlock(ptl); - __migration_entry_wait(mm, (pte_t *)pmd, ptl); + __migration_entry_wait_huge((pte_t *)pmd, ptl); goto retry; } /* diff --git a/mm/migrate.c b/mm/migrate.c index a14c6d5ceafc..3359a6e169bb 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -315,13 +315,28 @@ void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, __migration_entry_wait(mm, ptep, ptl); } -void migration_entry_wait_huge(struct vm_area_struct *vma, - struct mm_struct *mm, pte_t *pte) +#ifdef CONFIG_HUGETLB_PAGE +void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl) { - spinlock_t *ptl = huge_pte_lockptr(hstate_vma(vma), mm, pte); - __migration_entry_wait(mm, pte, ptl); + pte_t pte; + + spin_lock(ptl); + pte = huge_ptep_get(ptep); + + if (unlikely(!is_hugetlb_entry_migration(pte))) + spin_unlock(ptl); + else + migration_entry_wait_on_locked(pte_to_swp_entry(pte), NULL, ptl); } +void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte) +{ + spinlock_t *ptl = huge_pte_lockptr(hstate_vma(vma), vma->vm_mm, pte); + + __migration_entry_wait_huge(pte, ptl); +} +#endif + #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd) { -- 2.23.0