From patchwork Wed Oct 7 20:50:43 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: srinivas pandruvada X-Patchwork-Id: 7347291 X-Patchwork-Delegate: rjw@sisk.pl Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 45FC3BEEA4 for ; Wed, 7 Oct 2015 20:51:28 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6289520623 for ; Wed, 7 Oct 2015 20:51:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6757D2073B for ; Wed, 7 Oct 2015 20:51:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753952AbbJGUvZ (ORCPT ); Wed, 7 Oct 2015 16:51:25 -0400 Received: from mga09.intel.com ([134.134.136.24]:8113 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753605AbbJGUvY (ORCPT ); Wed, 7 Oct 2015 16:51:24 -0400 Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga102.jf.intel.com with ESMTP; 07 Oct 2015 13:51:23 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,651,1437462000"; d="scan'208";a="659874066" Received: from spandruv-desk3.amr.corp.intel.com (HELO spandruv-desk3.jf.intel.com) ([10.7.199.153]) by orsmga003.jf.intel.com with ESMTP; 07 Oct 2015 13:51:23 -0700 From: Srinivas Pandruvada To: rafael.j.wysocki@intel.com, viresh.kumar@linaro.org Cc: linux-pm@vger.kernel.org, Srinivas Pandruvada Subject: [PATCH v1 1/2] cpufreq: acpi_cpufreq: prevent crash on reading freqdomain_cpus Date: Wed, 7 Oct 2015 13:50:43 -0700 Message-Id: <1444251044-11231-2-git-send-email-srinivas.pandruvada@linux.intel.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1444251044-11231-1-git-send-email-srinivas.pandruvada@linux.intel.com> References: <1444251044-11231-1-git-send-email-srinivas.pandruvada@linux.intel.com> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When freqdomain_cpus attribute is read from an offlined cpu, it will cause crash. This change prevents calling cpufreq_show_cpus when policy driver_data is NULL. Crash info: [ 170.814949] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 [ 170.814990] IP: [] _find_next_bit.part.0+0x10/0x70 [ 170.815021] PGD 227d30067 PUD 229e56067 PMD 0 [ 170.815043] Oops: 0000 [#2] SMP [ 170.816022] CPU: 3 PID: 3121 Comm: cat Tainted: G D OE 4.3.0-rc3+ #33 ... ... [ 170.816657] Call Trace: [ 170.816672] [] ? find_next_bit+0x15/0x20 [ 170.816696] [] cpufreq_show_cpus+0x5c/0xd0 [ 170.816722] [] show_freqdomain_cpus+0x19/0x20 [acpi_cpufreq] [ 170.816749] [] show+0x3b/0x60 [ 170.816769] [] sysfs_kf_seq_show+0xbc/0x130 [ 170.816793] [] kernfs_seq_show+0x23/0x30 [ 170.816816] [] seq_read+0xec/0x390 [ 170.816837] [] kernfs_fop_read+0x10a/0x160 [ 170.816861] [] __vfs_read+0x37/0x100 [ 170.816883] [] ? security_file_permission+0xa0/0xc0 [ 170.816909] [] vfs_read+0x83/0x130 [ 170.816930] [] SyS_read+0x55/0xc0 ... ... [ 170.817185] ---[ end trace bc6eadf82b2b965a ]--- Signed-off-by: Srinivas Pandruvada Acked-by: Viresh Kumar --- drivers/cpufreq/acpi-cpufreq.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c index 7982772..cec1ee2 100644 --- a/drivers/cpufreq/acpi-cpufreq.c +++ b/drivers/cpufreq/acpi-cpufreq.c @@ -149,6 +149,9 @@ static ssize_t show_freqdomain_cpus(struct cpufreq_policy *policy, char *buf) { struct acpi_cpufreq_data *data = policy->driver_data; + if (unlikely(!data)) + return -ENODEV; + return cpufreq_show_cpus(data->freqdomain_cpus, buf); }