From patchwork Tue Dec 26 11:22:26 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Zeng X-Patchwork-Id: 10133037 X-Patchwork-Delegate: rui.zhang@intel.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 95C2360388 for ; Tue, 26 Dec 2017 11:38:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 870A42E338 for ; Tue, 26 Dec 2017 11:38:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7BB792E33D; Tue, 26 Dec 2017 11:38:28 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A3ADA2E338 for ; Tue, 26 Dec 2017 11:38:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751332AbdLZLi0 (ORCPT ); Tue, 26 Dec 2017 06:38:26 -0500 Received: from [210.13.100.6] ([210.13.100.6]:31636 "EHLO mail2012.asrmicro.com" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750776AbdLZLiZ (ORCPT ); Tue, 26 Dec 2017 06:38:25 -0500 X-Greylist: delayed 917 seconds by postgrey-1.27 at vger.kernel.org; Tue, 26 Dec 2017 06:38:25 EST Received: from localhost (10.1.50.33) by mail2012.asrmicro.com (10.1.24.123) with Microsoft SMTP Server (TLS) id 15.0.847.32; Tue, 26 Dec 2017 19:22:29 +0800 From: Yi Zeng To: , , , CC: Yi Zeng Subject: [PATCH] thermal: power_allocator: fix one race condition issue for thermal_instances list Date: Tue, 26 Dec 2017 19:22:26 +0800 Message-ID: <1514287346-6224-1-git-send-email-yizeng@asrmicro.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 X-Originating-IP: [10.1.50.33] X-ClientProxiedBy: mail2012.asrmicro.com (10.1.24.123) To mail2012.asrmicro.com (10.1.24.123) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When invoking allow_maximum_power and traverse tz->thermal_instances, we should grab thermal_zone_device->lock to avoid race condition. For example, during the system reboot, if the mali GPU device implements device shutdown callback and unregister GPU devfreq cooling device, the deleted list head may be accessed to cause panic, as the following log shows: [ 33.551070] c3 25 (kworker/3:0) Unable to handle kernel paging request at virtual address dead000000000070 [ 33.566708] c3 25 (kworker/3:0) pgd = ffffffc0ed290000 [ 33.572071] c3 25 (kworker/3:0) [dead000000000070] *pgd=00000001ed292003, *pud=00000001ed292003, *pmd=0000000000000000 [ 33.581515] c3 25 (kworker/3:0) Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 33.599761] c3 25 (kworker/3:0) CPU: 3 PID: 25 Comm: kworker/3:0 Not tainted 4.4.35+ #912 [ 33.614137] c3 25 (kworker/3:0) Workqueue: events_freezable thermal_zone_device_check [ 33.620245] c3 25 (kworker/3:0) task: ffffffc0f32e4200 ti: ffffffc0f32f0000 task.ti: ffffffc0f32f0000 [ 33.629466] c3 25 (kworker/3:0) PC is at power_allocator_throttle+0x7c8/0x8a4 [ 33.636609] c3 25 (kworker/3:0) LR is at power_allocator_throttle+0x808/0x8a4 [ 33.643742] c3 25 (kworker/3:0) pc : [] lr : [] pstate: 20000145 [ 33.652874] c3 25 (kworker/3:0) sp : ffffffc0f32f3bb0 [ 34.468519] c3 25 (kworker/3:0) Process kworker/3:0 (pid: 25, stack limit = 0xffffffc0f32f0020) [ 34.477220] c3 25 (kworker/3:0) Stack: (0xffffffc0f32f3bb0 to 0xffffffc0f32f4000) [ 34.819822] c3 25 (kworker/3:0) Call trace: [ 34.824021] c3 25 (kworker/3:0) Exception stack(0xffffffc0f32f39c0 to 0xffffffc0f32f3af0) [ 34.924993] c3 25 (kworker/3:0) [] power_allocator_throttle+0x7c8/0x8a4 [ 34.933184] c3 25 (kworker/3:0) [] handle_thermal_trip.part.25+0x70/0x224 [ 34.941545] c3 25 (kworker/3:0) [] thermal_zone_device_update+0xc0/0x20c [ 34.949818] c3 25 (kworker/3:0) [] thermal_zone_device_check+0x20/0x2c [ 34.957924] c3 25 (kworker/3:0) [] process_one_work+0x168/0x458 [ 34.965414] c3 25 (kworker/3:0) [] worker_thread+0x13c/0x4b4 [ 34.972650] c3 25 (kworker/3:0) [] kthread+0xe8/0xfc [ 34.979187] c3 25 (kworker/3:0) [] ret_from_fork+0x10/0x40 [ 34.986244] c3 25 (kworker/3:0) Code: f9405e73 eb1302bf d102e273 54ffc460 (b9402a61) [ 34.994339] c3 25 (kworker/3:0) ---[ end trace 32057901e3b7e1db ]--- Signed-off-by: Yi Zeng --- drivers/thermal/power_allocator.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/thermal/power_allocator.c b/drivers/thermal/power_allocator.c index b4d3116..3055f9a 100644 --- a/drivers/thermal/power_allocator.c +++ b/drivers/thermal/power_allocator.c @@ -523,6 +523,7 @@ static void allow_maximum_power(struct thermal_zone_device *tz) struct thermal_instance *instance; struct power_allocator_params *params = tz->governor_data; + mutex_lock(&tz->lock); list_for_each_entry(instance, &tz->thermal_instances, tz_node) { if ((instance->trip != params->trip_max_desired_temperature) || (!cdev_is_power_actor(instance->cdev))) @@ -534,6 +535,7 @@ static void allow_maximum_power(struct thermal_zone_device *tz) mutex_unlock(&instance->cdev->lock); thermal_cdev_update(instance->cdev); } + mutex_unlock(&tz->lock); } /**