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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,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 B237EC3F2D1 for ; Mon, 2 Mar 2020 07:18:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 828AC24699 for ; Mon, 2 Mar 2020 07:18:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="d794cEm4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726654AbgCBHSg (ORCPT ); Mon, 2 Mar 2020 02:18:36 -0500 Received: from mail-pf1-f194.google.com ([209.85.210.194]:45404 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726204AbgCBHSf (ORCPT ); Mon, 2 Mar 2020 02:18:35 -0500 Received: by mail-pf1-f194.google.com with SMTP id 2so5111780pfg.12; Sun, 01 Mar 2020 23:18:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=SGYHPYDByh3jgM9qVULEcWknYrO2Uv9Ry5lUP1fq0cU=; b=d794cEm4/jGpeACslEH4kzP+y3+j3IKtTRsaga+yf8sTnlUAOHBn9tuqwJ0yTx7dYD Vs5dCBO3yx1zEVc5/S/paU18egxiByiViTHUPoYsgMntp9MzgkDYYhpeke8BwVAUzn0S mYwv/3Umhk0keqQOdcZNCw6dr2xV4gj3fcytzBnAgN5xdfZFUMSrWJlD0cqJn5JKqk0c wiZrpC9JrH8n83UN/39qy5xXjxooSWLv7ccsoyFQZoS5ajgtks7vD7Rnt9M4ZoJ02q3T Uha1nYWlfu+/3rQzkUrK4LjW5Yi2jWtSMYEmF0Pc3CdiE1SVp2qGy75z2ub0IwNdf7WM hJ7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=SGYHPYDByh3jgM9qVULEcWknYrO2Uv9Ry5lUP1fq0cU=; b=mssg4U1Yxc+oVIpkVigBfNHDcps/e0VIAECCo1Pe2m1ZEoUfkfrjChvklC9HwNVQjO hrVvcrI+TItLBLw3yhcXzZXFjhv2Q25mpagOQbEkblQv+UftYUkIUwucpOvhIPqEYJCG ZjLfGgCmJ7HgZBqIsT9GSyCJJc2+CRez3tMQBlaB4CRV4sSI+0Vsst9EAFfS1qAE4RPW Ytb9EXDyPK13iPdi9l/1X8MwEwPgk39KHTJ7A55Xle4pHgQ8xssz02RfzCzQ3G8eOG+8 VLJS2oNq0wX282XmQZmFyBnPicmbZcQLKZN/x60lERz1BxIURaQd1MPtWA2p9UE2RikU tQCg== X-Gm-Message-State: APjAAAVK3aN/9s7gEj51oJmjKSb9SUvKrklhnmcEkiUuNSdyiUnKn+mO 3h6iLISPKOUsx6rgBRAbXFNP221pNS9t7w== X-Google-Smtp-Source: APXvYqxUxPCh2zTtls/G8B2nA/ioRKUNFEaXw0JBRt/6l+WtrYbNC0mZhQKV8wWHP7GixIC12DR/8g== X-Received: by 2002:a63:2c50:: with SMTP id s77mr17537810pgs.182.1583133514798; Sun, 01 Mar 2020 23:18:34 -0800 (PST) Received: from kernel.DHCP ([120.244.140.54]) by smtp.googlemail.com with ESMTPSA id z127sm19257989pgb.64.2020.03.01.23.18.10 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 01 Mar 2020 23:18:33 -0800 (PST) From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Naresh Kamboju Subject: [PATCH] KVM: X86: Fix dereference null cpufreq policy Date: Mon, 2 Mar 2020 15:15:36 +0800 Message-Id: <1583133336-7832-1-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wanpeng Li Naresh Kamboju reported: Linux version 5.6.0-rc4 (oe-user@oe-host) (gcc version (GCC)) #1 SMP Sun Mar 1 22:59:08 UTC 2020 kvm: no hardware support BUG: kernel NULL pointer dereference, address: 000000000000028c #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.6.0-rc4 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), 04/01/2014 RIP: 0010:kobject_put+0x12/0x1c0 Call Trace: cpufreq_cpu_put+0x15/0x20 kvm_arch_init+0x1f6/0x2b0 kvm_init+0x31/0x290 ? svm_check_processor_compat+0xd/0xd ? svm_check_processor_compat+0xd/0xd svm_init+0x21/0x23 do_one_initcall+0x61/0x2f0 ? rdinit_setup+0x30/0x30 ? rcu_read_lock_sched_held+0x4f/0x80 kernel_init_freeable+0x219/0x279 ? rest_init+0x250/0x250 kernel_init+0xe/0x110 ret_from_fork+0x27/0x50 Modules linked in: CR2: 000000000000028c ---[ end trace 239abf40c55c409b ]--- RIP: 0010:kobject_put+0x12/0x1c0 cpufreq policy which is get by cpufreq_cpu_get() can be NULL if it is failure, this patch takes care of it. Fixes: aaec7c03de (KVM: x86: avoid useless copy of cpufreq policy) Reported-by: Naresh Kamboju Cc: Naresh Kamboju Signed-off-by: Wanpeng Li --- arch/x86/kvm/x86.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 5de2006..3156e25 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7195,10 +7195,12 @@ static void kvm_timer_init(void) cpu = get_cpu(); policy = cpufreq_cpu_get(cpu); - if (policy && policy->cpuinfo.max_freq) - max_tsc_khz = policy->cpuinfo.max_freq; + if (policy) { + if (policy->cpuinfo.max_freq) + max_tsc_khz = policy->cpuinfo.max_freq; + cpufreq_cpu_put(policy); + } put_cpu(); - cpufreq_cpu_put(policy); #endif cpufreq_register_notifier(&kvmclock_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER); -- 2.7.4