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=-17.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 021C3C64E8A for ; Mon, 30 Nov 2020 13:22:56 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 90F68206F9 for ; Mon, 30 Nov 2020 13:22:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="iBLlxHxY"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="o1NC+rnv" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 90F68206F9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=NAH9GZbxuuKHRbQXnghRv3nCbkl0ca+Ww0hsmuqAgRc=; b=iBLlxHxYO995s75UI9k/Vj16G shOVevONdjjJrTNpTJrg63kq8gnV+Jatn6tlx8gXqkKOkTR2s4ClqNColQyQb1CPPOzulvN9QvSnU AeeCqBoy0P4ZR6elhsp7wbcTrXwr/aaxonE+kwHSyLdrxZVtC4Pn4t3OenfY33ZbthfWXX3Ufjqx8 BHNNn5toHGPTf1/6NOeI+pxAsSJMqW5paQH4hL2iKMwMGAVRI1T1crxnNZ/Ov42nhDIPT4xHGNeos 5hZYoH4GFcHoswR51RFUnOImuu+DLQr834FGZduoPge9L3Z9oh+/SI7nFpnGoc5wduy6MympcN0+5 A92WtUX3w==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kjj7g-0000cZ-AF; Mon, 30 Nov 2020 13:21:44 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kjj7d-0000bF-8D for linux-arm-kernel@lists.infradead.org; Mon, 30 Nov 2020 13:21:42 +0000 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 48334206F9; Mon, 30 Nov 2020 13:21:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606742500; bh=gp/c1E7Z/fJDz9MSxVD5z46kbUzUAVwzY3qc3WzdfAw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=o1NC+rnv0ct8v2OvLOXV/3bHWyPXa1peKB6ER4KOtm7UqFOxIhAhpuXKIqRi8NAdb pMM18yWdbu20bY679BQLRr69tRIT6UVJcvY88CM9WJMv+7OOV9XyoGeBE+KcYXYU2j WId7gM2IrW69ZGYIT4hh3nForfeKOmmxKV7nqxWg= Date: Mon, 30 Nov 2020 13:21:33 +0000 From: Will Deacon To: Yanan Wang Subject: Re: [RFC PATCH 1/3] KVM: arm64: Fix possible memory leak in kvm stage2 Message-ID: <20201130132133.GA24837@willie-the-truck> References: <20201130121847.91808-1-wangyanan55@huawei.com> <20201130121847.91808-2-wangyanan55@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201130121847.91808-2-wangyanan55@huawei.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201130_082141_382939_85E895E2 X-CRM114-Status: GOOD ( 19.43 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: jiangkunkun@huawei.com, Gavin Shan , Suzuki K Poulose , Marc Zyngier , wangjingyi11@huawei.com, Quentin Perret , lushenming@huawei.com, linux-kernel@vger.kernel.org, yezengruan@huawei.com, James Morse , linux-arm-kernel@lists.infradead.org, Catalin Marinas , yuzenghui@huawei.com, wanghaibin.wang@huawei.com, zhukeqian1@huawei.com, Julien Thierry Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Nov 30, 2020 at 08:18:45PM +0800, Yanan Wang wrote: > 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. Did you find this by inspection, or did you hit this in practice? I'd be interested to see the backtrace for mapping over an existing mapping. > 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)); This is also used for the hypervisor stage-1 page-table, so I'd prefer to leave this function as-is. > 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; Isn't this hunk alone sufficient to solve the problem? Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel