From 703cbaa601ff3fb554d1246c336ba727cc083ea0 Mon Sep 17 00:00:00 2001 From: Bo Yan Date: Tue, 23 Jan 2018 13:57:55 -0800 Subject: cpufreq: Skip cpufreq resume if it's not suspended 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; The fix is to check cpufreq_suspended first, if it's false, that means cpufreq_suspend was not called in the first place, so do not resume cpufreq. Signed-off-by: Bo Yan Acked-by: Viresh Kumar [ rjw: Dropped printing a message ] Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/cpufreq') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 421f318c0e66..de33ebf008ad 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1686,6 +1686,9 @@ void cpufreq_resume(void) if (!cpufreq_driver) return; + if (unlikely(!cpufreq_suspended)) + return; + cpufreq_suspended = false; if (!has_target() && !cpufreq_driver->resume) -- cgit v1.2.3-59-g8ed1b