From patchwork Thu Jan 25 19:15:45 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bo Yan X-Patchwork-Id: 10184703 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 905DD60233 for ; Thu, 25 Jan 2018 19:15:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7ED9E2891E for ; Thu, 25 Jan 2018 19:15:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 70331289BF; Thu, 25 Jan 2018 19:15:53 +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 B63E62891E for ; Thu, 25 Jan 2018 19:15:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751170AbeAYTPv (ORCPT ); Thu, 25 Jan 2018 14:15:51 -0500 Received: from hqemgate15.nvidia.com ([216.228.121.64]:17444 "EHLO hqemgate15.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751108AbeAYTPu (ORCPT ); Thu, 25 Jan 2018 14:15:50 -0500 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate15.nvidia.com id ; Thu, 25 Jan 2018 11:15:53 -0800 Received: from HQMAIL108.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Thu, 25 Jan 2018 11:15:50 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Thu, 25 Jan 2018 11:15:50 -0800 Received: from HQMAIL105.nvidia.com (172.20.187.12) by HQMAIL108.nvidia.com (172.18.146.13) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Thu, 25 Jan 2018 19:15:50 +0000 Received: from byan-linux.NVIDIA.COM (10.124.1.5) by HQMAIL105.nvidia.com (172.20.187.12) with Microsoft SMTP Server (TLS) id 15.0.1347.2 via Frontend Transport; Thu, 25 Jan 2018 19:15:50 +0000 From: Bo Yan To: , , CC: , , Bo Yan Subject: [PATCH v2] cpufreq: skip cpufreq resume if it's not suspended Date: Thu, 25 Jan 2018 11:15:45 -0800 Message-ID: <1516907745-13508-1-git-send-email-byan@nvidia.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1744712.rO4QOLozun@aspire.rjw.lan> References: <1744712.rO4QOLozun@aspire.rjw.lan> X-NVConfidentiality: public MIME-Version: 1.0 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 cpufreq_resume can be called even without preceding cpufreq_suspend. This can happen in following scenario: suspend_devices_and_enter --> dpm_suspend_start --> dpm_prepare --> device_prepare : this function errors out --> dpm_suspend: this is skipped due to dpm_prepare failure this means cpufreq_suspend is skipped over --> goto Recover_platform, due to previous error --> goto Resume_devices --> dpm_resume_end --> dpm_resume --> cpufreq_resume In case schedutil is used as frequency governor, cpufreq_resume will eventually call sugov_start, which does following: memset(sg_cpu, 0, sizeof(*sg_cpu)); .... This effectively erases function pointer for frequency update, causing crash later on. The function pointer would have been set correctly if subsequent cpufreq_add_update_util_hook runs successfully, but that function returns earlier because cpufreq_suspend was not called: if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu))) return; Ideally, suspend should succeed, then things will be fine. But even in case of suspend failure, system should not crash. The fix is to check the pm_transition status in dpm_resume. if pm_transition.event == PMSG_ON, we know for sure dpm_suspend has not been called, so do not call cpufreq_resume. Signed-off-by: Bo Yan --- drivers/base/power/main.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 08744b572af6..39829d7a9311 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -921,6 +921,7 @@ static void async_resume(void *data, async_cookie_t cookie) void dpm_resume(pm_message_t state) { struct device *dev; + bool suspended = (pm_transition.event != PM_EVENT_ON); ktime_t starttime = ktime_get(); trace_suspend_resume(TPS("dpm_resume"), state.event, true); @@ -964,7 +965,8 @@ void dpm_resume(pm_message_t state) async_synchronize_full(); dpm_show_time(starttime, state, 0, NULL); - cpufreq_resume(); + if (likely(suspended)) + cpufreq_resume(); trace_suspend_resume(TPS("dpm_resume"), state.event, false); }