From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Boyd Subject: [PATCH v2] cpufreq: Don't use smp_processor_id() in preemptible context Date: Wed, 28 Aug 2013 14:24:45 -0700 Message-ID: <1377725085-16798-1-git-send-email-sboyd@codeaurora.org> References: <521E24CE.9090407@codeaurora.org> Return-path: In-Reply-To: <521E24CE.9090407@codeaurora.org> Sender: cpufreq-owner@vger.kernel.org To: Viresh Kumar Cc: linux-kernel@vger.kernel.org, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org, "Rafael J . Wysocki" List-Id: linux-pm@vger.kernel.org Workqueues are preemptible even if works are queued on them with queue_work_on(). Let's use raw_smp_processor_id() here to silence the warning. BUG: using smp_processor_id() in preemptible [00000000] code: kworker/3:2/674 caller is gov_queue_work+0x28/0xb0 CPU: 0 PID: 674 Comm: kworker/3:2 Tainted: G W 3.10.0 #30 Workqueue: events od_dbs_timer [] (unwind_backtrace+0x0/0x11c) from [] (show_stack+0x10/0x14) [] (show_stack+0x10/0x14) from [] (debug_smp_processor_id+0xbc/0xf0) [] (debug_smp_processor_id+0xbc/0xf0) from [] (gov_queue_work+0x28/0xb0) [] (gov_queue_work+0x28/0xb0) from [] (od_dbs_timer+0x108/0x134) [] (od_dbs_timer+0x108/0x134) from [] (process_one_work+0x25c/0x444) [] (process_one_work+0x25c/0x444) from [] (worker_thread+0x200/0x344) [] (worker_thread+0x200/0x344) from [] (kthread+0xa0/0xb0) [] (kthread+0xa0/0xb0) from [] (ret_from_fork+0x14/0x3c) Signed-off-by: Stephen Boyd --- drivers/cpufreq/cpufreq_governor.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index b9b20fd..bfbcf9a 100644 --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -137,7 +137,14 @@ void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy, return; if (!all_cpus) { - __gov_queue_work(smp_processor_id(), dbs_data, delay); + /* + * Use raw_smp_processor_id() to avoid preemptible warnings. + * We know that this is only called with all_cpus == false from + * works that have been queued with *_work_on() functions and + * those works are canceled during CPU_DOWN_PREPARE so they + * can't possibly run on any other CPU. + */ + __gov_queue_work(raw_smp_processor_id(), dbs_data, delay); } else { for_each_cpu(i, policy->cpus) __gov_queue_work(i, dbs_data, delay); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation