From patchwork Tue Sep 29 11:00:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 290742 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=-13.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 EDB65C4727F for ; Tue, 29 Sep 2020 12:43:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C025208FE for ; Tue, 29 Sep 2020 12:43:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601383389; bh=RkAgZ0llnIywDojBShVlZTmNEJcf13A5yJpo8vi/diU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=hekM8yWxx3+FY0XHLsyEqWPTb1FNmudqN+rpA9McgIR/0JcWHXwUpu0mpDAgiNcFG AyJATrqr8B8s6tFlWo9s6CDZVJ0YBJU0L4NpYk/zJHUL8O2G5VkzjrMJxN1zMxo6CX S2ALvlKAGzGXoABhVR05Sf2Rr14ClZeHP9W/IJF4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729447AbgI2Mm5 (ORCPT ); Tue, 29 Sep 2020 08:42:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:50706 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729129AbgI2LKD (ORCPT ); Tue, 29 Sep 2020 07:10:03 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 711A321D46; Tue, 29 Sep 2020 11:10:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601377803; bh=RkAgZ0llnIywDojBShVlZTmNEJcf13A5yJpo8vi/diU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wp6gLZfrTKuNimrQonCZ+HmyINOB+p6QVjEGr7Jv8kqilqqv3rt88Fc7sBzVP8RpU N59JpTSkpN/OrZyJniaPw2ueNq5kBntIbas8GDASVGwSHjwOaXKf/aCeuEki9PGZuj tQUhmahKOybI1Xp5tLimL7V5WFpEv1OiBf09oRk8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Steve Rutherford , Jon Cargille , Jim Mattson , Paolo Bonzini , Sasha Levin Subject: [PATCH 4.9 077/121] KVM: Remove CREATE_IRQCHIP/SET_PIT2 race Date: Tue, 29 Sep 2020 13:00:21 +0200 Message-Id: <20200929105933.995631521@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105930.172747117@linuxfoundation.org> References: <20200929105930.172747117@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Steve Rutherford [ Upstream commit 7289fdb5dcdbc5155b5531529c44105868a762f2 ] Fixes a NULL pointer dereference, caused by the PIT firing an interrupt before the interrupt table has been initialized. SET_PIT2 can race with the creation of the IRQchip. In particular, if SET_PIT2 is called with a low PIT timer period (after the creation of the IOAPIC, but before the instantiation of the irq routes), the PIT can fire an interrupt at an uninitialized table. Signed-off-by: Steve Rutherford Signed-off-by: Jon Cargille Reviewed-by: Jim Mattson Message-Id: <20200416191152.259434-1-jcargill@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- arch/x86/kvm/x86.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6b7faa14c27bb..3c0f9be107e42 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4263,10 +4263,13 @@ long kvm_arch_vm_ioctl(struct file *filp, r = -EFAULT; if (copy_from_user(&u.ps, argp, sizeof u.ps)) goto out; + mutex_lock(&kvm->lock); r = -ENXIO; if (!kvm->arch.vpit) - goto out; + goto set_pit_out; r = kvm_vm_ioctl_set_pit(kvm, &u.ps); +set_pit_out: + mutex_unlock(&kvm->lock); break; } case KVM_GET_PIT2: { @@ -4286,10 +4289,13 @@ long kvm_arch_vm_ioctl(struct file *filp, r = -EFAULT; if (copy_from_user(&u.ps2, argp, sizeof(u.ps2))) goto out; + mutex_lock(&kvm->lock); r = -ENXIO; if (!kvm->arch.vpit) - goto out; + goto set_pit2_out; r = kvm_vm_ioctl_set_pit2(kvm, &u.ps2); +set_pit2_out: + mutex_unlock(&kvm->lock); break; } case KVM_REINJECT_CONTROL: {