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authorBo Yan <byan@nvidia.com>2018-01-23 22:57:55 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-02-05 11:03:33 +0100
commit703cbaa601ff3fb554d1246c336ba727cc083ea0 (patch)
tree1d6c54f84f12ed6de8b299cb6b5976c504e40550 /drivers/cpufreq/cpufreq.c
parentMerge tag 'pm-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafa... (diff)
downloadlinux-703cbaa601ff3fb554d1246c336ba727cc083ea0.tar.xz
linux-703cbaa601ff3fb554d1246c336ba727cc083ea0.zip
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 <byan@nvidia.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> [ rjw: Dropped printing a message ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
-rw-r--r--drivers/cpufreq/cpufreq.c3
1 files changed, 3 insertions, 0 deletions
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)