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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 83B73C54FCB for ; Thu, 23 Apr 2020 15:40:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6360120767 for ; Thu, 23 Apr 2020 15:40:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587656439; bh=n+o2mqQRZN2hZz3P/W26d4psiY47gyRfHELtjEZmnW4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=BHy+FLISLu+W74g5TW6S/K9rqQ7N8OUs8tMzqG3TiPPibasUqayL8ZOW0ZDDp6KEA XbwbdKkNeojYKiWAEhwm93B36X3pFmhKbG2Epc9VzcFigDJm1DnVe9iq51KlOK49+h ObRv72drnBZlFsORpqcyF8ogCFVbZJ7U/QRbo88g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729393AbgDWPki (ORCPT ); Thu, 23 Apr 2020 11:40:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:51390 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729312AbgDWPkh (ORCPT ); Thu, 23 Apr 2020 11:40:37 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (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 B283D2166E; Thu, 23 Apr 2020 15:40:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587656436; bh=n+o2mqQRZN2hZz3P/W26d4psiY47gyRfHELtjEZmnW4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Qx9rsDifcJ3+Njhk6JU+Pb2nzh/0EoTXPz58KxuZqaD2uSItsJerIqWPKfGNybjlf w+UHQ+7zEmbbOuCNmcsIlY0o/dCZJwuUUU2JUGq/cQYPIe82J0Kr1AKIw1koYsd4Tf 5Fx/xMDflxU6h3CzdGZLbMHWJUIf5iMRBG58Cpn8= Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jRdxr-005oPM-3d; Thu, 23 Apr 2020 16:40:35 +0100 From: Marc Zyngier To: Paolo Bonzini Cc: Alexandru Elisei , =?UTF-8?q?Andr=C3=A9=20Przywara?= , Christoffer Dall , Julien Grall , Zenghui Yu , James Morse , Julien Thierry , Suzuki K Poulose , kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu Subject: [PATCH 7/8] KVM: arm64: vgic-v3: Retire all pending LPIs on vcpu destroy Date: Thu, 23 Apr 2020 16:40:08 +0100 Message-Id: <20200423154009.4113562-8-maz@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200423154009.4113562-1-maz@kernel.org> References: <20200423154009.4113562-1-maz@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: pbonzini@redhat.com, alexandru.elisei@arm.com, andre.przywara@arm.com, christoffer.dall@arm.com, julien@xen.org, yuzenghui@huawei.com, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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(). This was detected by kmemleak on almost every guest destroy, the backtrace is as follows: unreferenced object 0xffff80725aed5500 (size 128): comm "CPU 5/KVM", pid 40711, jiffies 4298024754 (age 166366.512s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 08 01 a9 73 6d 80 ff ff ...........sm... c8 61 ee a9 00 20 ff ff 28 1e 55 81 6c 80 ff ff .a... ..(.U.l... backtrace: [<000000004bcaa122>] kmem_cache_alloc_trace+0x2dc/0x418 [<0000000069c7dabb>] vgic_add_lpi+0x88/0x418 [<00000000bfefd5c5>] vgic_its_cmd_handle_mapi+0x4dc/0x588 [<00000000cf993975>] vgic_its_process_commands.part.5+0x484/0x1198 [<000000004bd3f8e3>] vgic_its_process_commands+0x50/0x80 [<00000000b9a65b2b>] vgic_mmio_write_its_cwriter+0xac/0x108 [<0000000009641ebb>] dispatch_mmio_write+0xd0/0x188 [<000000008f79d288>] __kvm_io_bus_write+0x134/0x240 [<00000000882f39ac>] kvm_io_bus_write+0xe0/0x150 [<0000000078197602>] io_mem_abort+0x484/0x7b8 [<0000000060954e3c>] kvm_handle_guest_abort+0x4cc/0xa58 [<00000000e0d0cd65>] handle_exit+0x24c/0x770 [<00000000b44a7fad>] kvm_arch_vcpu_ioctl_run+0x460/0x1988 [<0000000025fb897c>] kvm_vcpu_ioctl+0x4f8/0xee0 [<000000003271e317>] do_vfs_ioctl+0x160/0xcd8 [<00000000e7f39607>] ksys_ioctl+0x98/0xd8 Fix it by retiring all pending LPIs in the ap_list on the destroy path. p.s. I can also reproduce it on a normal guest shutdown. It is because userspace still send LPIs to vcpu (through KVM_SIGNAL_MSI ioctl) while the guest is being shutdown and unable to handle it. A little strange though and haven't dig further... Reviewed-by: James Morse Signed-off-by: Zenghui Yu [maz: moved the distributor deallocation down to avoid an UAF splat] Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20200414030349.625-2-yuzenghui@huawei.com --- virt/kvm/arm/vgic/vgic-init.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c index a963b9d766b73..30dbec9fe0b4a 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. + */ + vgic_flush_pending_lpis(vcpu); + INIT_LIST_HEAD(&vgic_cpu->ap_list_head); } @@ -359,10 +365,10 @@ static void __kvm_vgic_destroy(struct kvm *kvm) vgic_debug_destroy(kvm); - kvm_vgic_dist_destroy(kvm); - kvm_for_each_vcpu(i, vcpu, kvm) kvm_vgic_vcpu_destroy(vcpu); + + kvm_vgic_dist_destroy(kvm); } void kvm_vgic_destroy(struct kvm *kvm) -- 2.26.2