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 X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNWANTED_LANGUAGE_BODY, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38120C64E7B for ; Mon, 30 Nov 2020 12:19:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DDCD6206D8 for ; Mon, 30 Nov 2020 12:19:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726708AbgK3MT5 (ORCPT ); Mon, 30 Nov 2020 07:19:57 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:9074 "EHLO szxga05-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726114AbgK3MT4 (ORCPT ); Mon, 30 Nov 2020 07:19:56 -0500 Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4Cl45T31PPzLxpp; Mon, 30 Nov 2020 20:18:37 +0800 (CST) Received: from DESKTOP-TMVL5KK.china.huawei.com (10.174.186.123) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.487.0; Mon, 30 Nov 2020 20:19:02 +0800 From: Yanan Wang To: , , Marc Zyngier , Catalin Marinas , Will Deacon , James Morse , "Julien Thierry" , Suzuki K Poulose , Gavin Shan , Quentin Perret CC: , , , , , , , Yanan Wang Subject: [RFC PATCH 1/3] KVM: arm64: Fix possible memory leak in kvm stage2 Date: Mon, 30 Nov 2020 20:18:45 +0800 Message-ID: <20201130121847.91808-2-wangyanan55@huawei.com> X-Mailer: git-send-email 2.8.4.windows.1 In-Reply-To: <20201130121847.91808-1-wangyanan55@huawei.com> References: <20201130121847.91808-1-wangyanan55@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.174.186.123] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When installing a new leaf pte onto an invalid ptep, we need to get_page(ptep). When just updating a valid leaf ptep, we shouldn't get_page(ptep). Incorrect page_count of translation tables might lead to memory leak, when unmapping a stage 2 memory range. Signed-off-by: Yanan Wang --- arch/arm64/kvm/hyp/pgtable.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 0271b4a3b9fe..696b6aa83faf 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -186,6 +186,7 @@ static bool kvm_set_valid_leaf_pte(kvm_pte_t *ptep, u64 pa, kvm_pte_t attr, return old == pte; smp_store_release(ptep, pte); + get_page(virt_to_page(ptep)); return true; } @@ -476,6 +477,7 @@ static bool stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level, /* There's an existing valid leaf entry, so perform break-before-make */ kvm_set_invalid_pte(ptep); kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, data->mmu, addr, level); + put_page(virt_to_page(ptep)); kvm_set_valid_leaf_pte(ptep, phys, data->attr, level); out: data->phys += granule; @@ -512,7 +514,7 @@ static int stage2_map_walk_leaf(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, } if (stage2_map_walker_try_leaf(addr, end, level, ptep, data)) - goto out_get_page; + return 0; if (WARN_ON(level == KVM_PGTABLE_MAX_LEVELS - 1)) return -EINVAL; @@ -536,9 +538,8 @@ static int stage2_map_walk_leaf(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, } kvm_set_table_pte(ptep, childp); - -out_get_page: get_page(page); + return 0; } -- 2.19.1