From patchwork Wed Mar 27 15:32:14 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Pisati X-Patchwork-Id: 2351601 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 2765BDFE82 for ; Wed, 27 Mar 2013 15:35:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753014Ab3C0PcU (ORCPT ); Wed, 27 Mar 2013 11:32:20 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:60388 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752611Ab3C0PcT (ORCPT ); Wed, 27 Mar 2013 11:32:19 -0400 Received: from 2-230-238-136.ip204.fastwebnet.it ([2.230.238.136] helo=canonical.com) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1UKsKl-0007vm-FR; Wed, 27 Mar 2013 15:32:15 +0000 From: Paolo Pisati To: cpufreq@vger.kernel.org Cc: "Rafael J. Wysocki" , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] cpufreq: check OF /cpus presence before dereferencing it Date: Wed, 27 Mar 2013 16:32:14 +0100 Message-Id: <1364398334-19662-1-git-send-email-paolo.pisati@canonical.com> X-Mailer: git-send-email 1.7.10.4 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org check for '/cpus' presence before blindly dereferencing it: [ 4.181793] Unable to handle kernel NULL pointer dereference at virtual address 0000001c [ 4.181793] pgd = c0004000 [ 4.181823] [0000001c] *pgd=00000000 [ 4.181823] Internal error: Oops: 5 [#1] SMP ARM [ 4.181823] Modules linked in: [ 4.181823] CPU: 1 Tainted: G W (3.8.0-15-generic #25~hbankD) [ 4.181854] PC is at of_get_next_child+0x64/0x70 [ 4.181854] LR is at of_get_next_child+0x24/0x70 [ 4.181854] pc : [] lr : [] psr: 60000113 [ 4.181854] sp : ed891ec0 ip : ed891ec0 fp : ed891ed4 [ 4.181884] r10: c04dafd0 r9 : c098690c r8 : c0936208 [ 4.181884] r7 : ed890000 r6 : c0a63d00 r5 : 00000000 r4 : 00000000 [ 4.181884] r3 : 00000000 r2 : 00000000 r1 : 00000000 r0 : c0b2acc8 [ 4.181884] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel [ 4.181884] Control: 10c5387d Table: adcb804a DAC: 00000015 [ 4.181915] Process swapper/0 (pid: 1, stack limit = 0xed890238) [ 4.181915] Stack: (0xed891ec0 to 0xed892000) [ 4.181915] 1ec0: c09b7b70 00000007 ed891efc ed891ed8 c04daff4 c04fd9c0 00000000 c09b7b70 [ 4.181915] 1ee0: 00000007 c0a63d00 ed890000 c0936208 ed891f54 ed891f00 c00088e0 c04dafdc [ 4.181945] 1f00: ed891f54 ed891f10 c006e940 00000000 00000000 00000007 00000007 c08a4914 [ 4.181945] 1f20: 00000000 c07dbd30 c0a63d00 c09b7b70 00000007 c0a63d00 000000bc c0936208 [ 4.181945] 1f40: c098690c c0986914 ed891f94 ed891f58 c0936a40 c00087bc 00000007 00000007 [ 4.181976] 1f60: c0936208 be8bda20 b6eea010 c0a63d00 c064547c 00000000 00000000 00000000 [ 4.181976] 1f80: 00000000 00000000 ed891fac ed891f98 c0645498 c09368c8 00000000 00000000 [ 4.181976] 1fa0: 00000000 ed891fb0 c0014658 c0645488 00000000 00000000 00000000 00000000 [ 4.182006] 1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 4.182006] 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000 [ 4.182037] [] (of_get_next_child+0x64/0x70) from [] (cpu0_cpufreq_driver_init+0x24/0x284) [ 4.182067] [] (cpu0_cpufreq_driver_init+0x24/0x284) from [] (do_one_initcall+0x130/0x1b0) [ 4.182067] [] (do_one_initcall+0x130/0x1b0) from [] (kernel_init_freeable+0x184/0x24c) [ 4.182098] [] (kernel_init_freeable+0x184/0x24c) from [] (kernel_init+0x1c/0xf4) [ 4.182128] [] (kernel_init+0x1c/0xf4) from [] (ret_from_fork+0x14/0x20) [ 4.182128] Code: f57ff04f e320f004 e89da830 e89da830 (e595001c) [ 4.182128] ---[ end trace 634903a22e8609cb ]--- [ 4.182189] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b [ 4.182189] [ 4.642395] CPU0: stopping Signed-off-by: Paolo Pisati Acked-by: Viresh Kumar --- drivers/cpufreq/cpufreq-cpu0.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/cpufreq/cpufreq-cpu0.c b/drivers/cpufreq/cpufreq-cpu0.c index 4e5b7fb..f3e8f51 100644 --- a/drivers/cpufreq/cpufreq-cpu0.c +++ b/drivers/cpufreq/cpufreq-cpu0.c @@ -178,10 +178,16 @@ static struct cpufreq_driver cpu0_cpufreq_driver = { static int cpu0_cpufreq_probe(struct platform_device *pdev) { - struct device_node *np; + struct device_node *np, *tmp; int ret; - for_each_child_of_node(of_find_node_by_path("/cpus"), np) { + tmp = of_find_node_by_path("/cpus"); + if (!tmp) { + pr_err("failed to find OF /cpus\n"); + return -ENOENT; + } + + for_each_child_of_node(tmp, np) { if (of_get_property(np, "operating-points", NULL)) break; }