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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 9B1CFC54FCB for ; Thu, 23 Apr 2020 11:35:44 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 3964E2077D for ; Thu, 23 Apr 2020 11:35:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3964E2077D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id AB43D4B15D; Thu, 23 Apr 2020 07:35:43 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id I8NaGUDO-Ky7; Thu, 23 Apr 2020 07:35:42 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 574A64B14D; Thu, 23 Apr 2020 07:35:42 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 9DE4D4B142 for ; Thu, 23 Apr 2020 07:35:40 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id YGJimH6pdPSS for ; Thu, 23 Apr 2020 07:35:39 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 31B5B4B117 for ; Thu, 23 Apr 2020 07:35:39 -0400 (EDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9566531B; Thu, 23 Apr 2020 04:35:38 -0700 (PDT) Received: from [192.168.0.14] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 33A933F68F; Thu, 23 Apr 2020 04:35:37 -0700 (PDT) Subject: Re: [PATCH v3 5/6] KVM: arm64: vgic-v3: Retire all pending LPIs on vcpu destroy To: Marc Zyngier , Zenghui Yu References: <20200422161844.3848063-1-maz@kernel.org> <20200422161844.3848063-6-maz@kernel.org> From: James Morse Message-ID: <2a0d1542-1964-c818-aae8-76f9227676b8@arm.com> Date: Thu, 23 Apr 2020 12:35:30 +0100 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200422161844.3848063-6-maz@kernel.org> Content-Language: en-GB Cc: Julien Grall , kvm@vger.kernel.org, Andre Przywara , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu Hi Marc, Zenghui, On 22/04/2020 17:18, Marc Zyngier wrote: > From: Zenghui Yu > > It's likely that the vcpu fails to handle all virtual interrupts if > userspace decides to destroy it, leaving the pending ones stay in the > ap_list. If the un-handled one is a LPI, its vgic_irq structure will > be eventually leaked because of an extra refcount increment in > vgic_queue_irq_unlock(). > diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c > index a963b9d766b73..53ec9b9d9bc43 100644 > --- a/virt/kvm/arm/vgic/vgic-init.c > +++ b/virt/kvm/arm/vgic/vgic-init.c > @@ -348,6 +348,12 @@ void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) > { > struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu; > > + /* > + * Retire all pending LPIs on this vcpu anyway as we're > + * going to destroy it. > + */ Looking at the other caller, do we need something like: | if (vgic_cpu->lpis_enabled) ? > + vgic_flush_pending_lpis(vcpu); > + Otherwise, I get this on a gic-v2 machine!: [ 1742.187139] BUG: KASAN: use-after-free in vgic_flush_pending_lpis+0x250/0x2c0 [ 1742.194302] Read of size 8 at addr ffff0008e1bf1f28 by task qemu-system-aar/542 [ 1742.203140] CPU: 2 PID: 542 Comm: qemu-system-aar Not tainted 5.7.0-rc2-00006-g4fb0f7bb0e27 #2 [ 1742.211780] Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Jul 30 2018 [ 1742.222596] Call trace: [ 1742.225059] dump_backtrace+0x0/0x328 [ 1742.228738] show_stack+0x18/0x28 [ 1742.232071] dump_stack+0x134/0x1b0 [ 1742.235578] print_address_description.isra.0+0x6c/0x350 [ 1742.240910] __kasan_report+0x10c/0x180 [ 1742.244763] kasan_report+0x4c/0x68 [ 1742.248268] __asan_report_load8_noabort+0x30/0x48 [ 1742.253081] vgic_flush_pending_lpis+0x250/0x2c0 [ 1742.257718] __kvm_vgic_destroy+0x1cc/0x478 [ 1742.261919] kvm_vgic_destroy+0x30/0x48 [ 1742.265773] kvm_arch_destroy_vm+0x20/0x128 [ 1742.269976] kvm_put_kvm+0x3e0/0x8d0 [ 1742.273567] kvm_vm_release+0x3c/0x60 [ 1742.277248] __fput+0x218/0x630 [ 1742.280406] ____fput+0x10/0x20 [ 1742.283565] task_work_run+0xd8/0x1f0 [ 1742.287245] do_exit+0x87c/0x2640 [ 1742.290575] do_group_exit+0xd0/0x258 [ 1742.294254] __arm64_sys_exit_group+0x3c/0x48 [ 1742.298631] el0_svc_common.constprop.0+0x10c/0x348 [ 1742.303529] do_el0_svc+0x48/0xd0 [ 1742.306861] el0_sync_handler+0x11c/0x1b8 [ 1742.310888] el0_sync+0x158/0x180 [ 1742.315716] The buggy address belongs to the page: [ 1742.320529] page:fffffe002366fc40 refcount:0 mapcount:0 mapping:000000007e21d29f index:0x0 [ 1742.328821] flags: 0x2ffff00000000000() [ 1742.332678] raw: 2ffff00000000000 0000000000000000 ffffffff23660401 0000000000000000 [ 1742.340449] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 [ 1742.348215] page dumped because: kasan: bad access detected [ 1742.355304] Memory state around the buggy address: [ 1742.360115] ffff0008e1bf1e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 1742.367360] ffff0008e1bf1e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 1742.374606] >ffff0008e1bf1f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 1742.381851] ^ [ 1742.386399] ffff0008e1bf1f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 1742.393645] ffff0008e1bf2000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 1742.400889] ================================================================== [ 1742.408132] Disabling lock debugging due to kernel taint With that: Reviewed-by: James Morse Thanks, James _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm