Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964830AbaFIXIv (ORCPT ); Mon, 9 Jun 2014 19:08:51 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:56799 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932495AbaFIWpe (ORCPT ); Mon, 9 Jun 2014 18:45:34 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bibek Basu , Viresh Kumar , "Rafael J. Wysocki" Subject: [PATCH 3.14 25/78] cpufreq: remove race while accessing cur_policy Date: Mon, 9 Jun 2014 15:48:05 -0700 Message-Id: <20140609224814.163324850@linuxfoundation.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140609224813.282275135@linuxfoundation.org> References: <20140609224813.282275135@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bibek Basu commit c5450db85b828d0c46ac8fc570fb8a51bf07ac40 upstream. While accessing cur_policy during executing events CPUFREQ_GOV_START, CPUFREQ_GOV_STOP, CPUFREQ_GOV_LIMITS, same mutex lock is not taken, dbs_data->mutex, which leads to race and data corruption while running continious suspend resume test. This is seen with ondemand governor with suspend resume test using rtcwake. Unable to handle kernel NULL pointer dereference at virtual address 00000028 pgd = ed610000 [00000028] *pgd=adf11831, *pte=00000000, *ppte=00000000 Internal error: Oops: 17 [#1] PREEMPT SMP ARM Modules linked in: nvhost_vi CPU: 1 PID: 3243 Comm: rtcwake Not tainted 3.10.24-gf5cf9e5 #1 task: ee708040 ti: ed61c000 task.ti: ed61c000 PC is at cpufreq_governor_dbs+0x400/0x634 LR is at cpufreq_governor_dbs+0x3f8/0x634 pc : [] lr : [] psr: 600f0013 sp : ed61dcb0 ip : 000493e0 fp : c1cc14f0 r10: 00000000 r9 : 00000000 r8 : 00000000 r7 : eb725280 r6 : c1cc1560 r5 : eb575200 r4 : ebad7740 r3 : ee708040 r2 : ed61dca8 r1 : 001ebd24 r0 : 00000000 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 10c5387d Table: ad61006a DAC: 00000015 [] (cpufreq_governor_dbs+0x400/0x634) from [] (__cpufreq_governor+0x98/0x1b4) [] (__cpufreq_governor+0x98/0x1b4) from [] (__cpufreq_set_policy+0x250/0x320) [] (__cpufreq_set_policy+0x250/0x320) from [] (cpufreq_update_policy+0xcc/0x168) [] (cpufreq_update_policy+0xcc/0x168) from [] (cpu_freq_notify+0x68/0xdc) [] (cpu_freq_notify+0x68/0xdc) from [] (notifier_call_chain+0x4c/0x8c) [] (notifier_call_chain+0x4c/0x8c) from [] (__blocking_notifier_call_chain+0x50/0x68) [] (__blocking_notifier_call_chain+0x50/0x68) from [] (blocking_notifier_call_chain+0x20/0x28) [] (blocking_notifier_call_chain+0x20/0x28) from [] (pm_qos_update_bounded_target+0xd8/0x310) [] (pm_qos_update_bounded_target+0xd8/0x310) from [] (__pm_qos_update_request+0x64/0x70) [] (__pm_qos_update_request+0x64/0x70) from [] (tegra_pm_notify+0x114/0x134) [] (tegra_pm_notify+0x114/0x134) from [] (notifier_call_chain+0x4c/0x8c) [] (notifier_call_chain+0x4c/0x8c) from [] (__blocking_notifier_call_chain+0x50/0x68) [] (__blocking_notifier_call_chain+0x50/0x68) from [] (blocking_notifier_call_chain+0x20/0x28) [] (blocking_notifier_call_chain+0x20/0x28) from [] (pm_notifier_call_chain+0x1c/0x34) [] (pm_notifier_call_chain+0x1c/0x34) from [] (enter_state+0xec/0x128) [] (enter_state+0xec/0x128) from [] (pm_suspend+0x38/0xa4) [] (pm_suspend+0x38/0xa4) from [] (state_store+0x70/0xc0) [] (state_store+0x70/0xc0) from [] (kobj_attr_store+0x14/0x20) [] (kobj_attr_store+0x14/0x20) from [] (sysfs_write_file+0x104/0x184) [] (sysfs_write_file+0x104/0x184) from [] (vfs_write+0xd0/0x19c) [] (vfs_write+0xd0/0x19c) from [] (SyS_write+0x4c/0x78) [] (SyS_write+0x4c/0x78) from [] (ret_fast_syscall+0x0/0x30) Code: e1a00006 eb084346 e59b0020 e5951024 (e5903028) ---[ end trace 0488523c8f6b0f9d ]--- Signed-off-by: Bibek Basu Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/cpufreq/cpufreq_governor.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -366,6 +366,11 @@ int cpufreq_governor_dbs(struct cpufreq_ break; case CPUFREQ_GOV_LIMITS: + mutex_lock(&dbs_data->mutex); + if (!cpu_cdbs->cur_policy) { + mutex_unlock(&dbs_data->mutex); + break; + } mutex_lock(&cpu_cdbs->timer_mutex); if (policy->max < cpu_cdbs->cur_policy->cur) __cpufreq_driver_target(cpu_cdbs->cur_policy, @@ -375,6 +380,7 @@ int cpufreq_governor_dbs(struct cpufreq_ policy->min, CPUFREQ_RELATION_L); dbs_check_cpu(dbs_data, cpu); mutex_unlock(&cpu_cdbs->timer_mutex); + mutex_unlock(&dbs_data->mutex); break; } return 0; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/