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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 92073C43463 for ; Fri, 18 Sep 2020 02:43:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5091F214D8 for ; Fri, 18 Sep 2020 02:43:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600396995; bh=NvZmPw2C2uvbDgqyuHUaqE7UzXhi8hTw7mWaXV6zhTY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=MXwdgGrd5OL7YyG+OE2yeSrubZCYtF3ItGQk88FzD2dtmnd3buioNGP9weN/DlpVJ /AHrlOXmEnMmBINvA6NwjMD4oHmr+w10+WPQVtb9JsH1GBVG+4KEUBrUCGzvXZsktx TaX1GlRk3KN0QW7sdpOJFMKvE4tQv6mYEhDimx88= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729999AbgIRCnO (ORCPT ); Thu, 17 Sep 2020 22:43:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:36070 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728541AbgIRCK5 (ORCPT ); Thu, 17 Sep 2020 22:10:57 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 87A4E2311D; Fri, 18 Sep 2020 02:10:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395057; bh=NvZmPw2C2uvbDgqyuHUaqE7UzXhi8hTw7mWaXV6zhTY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sdpLoheP4/78s9yvJ5UYRRIIUZnCHcgAxNrAev3fPAbpFiQUifbgnLPT2KWJBgTUi DiMIryD/wU0cvOGfvfPS6hFkzv58HZXdvnqo6Gi5x9xZ96wy0qQC9sPrTJJ3zyp2EA 0yl77kMRThf7PVr2UeCD/4TxdMj54SbnUbvnsU+I= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Steve Rutherford , Jon Cargille , Jim Mattson , Paolo Bonzini , Sasha Levin , kvm@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 144/206] KVM: Remove CREATE_IRQCHIP/SET_PIT2 race Date: Thu, 17 Sep 2020 22:07:00 -0400 Message-Id: <20200918020802.2065198-144-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918020802.2065198-1-sashal@kernel.org> References: <20200918020802.2065198-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@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 430a4bc66f604..620ed1fa35119 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4668,10 +4668,13 @@ set_identity_unlock: 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: { @@ -4691,10 +4694,13 @@ set_identity_unlock: 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: { -- 2.25.1