summaryrefslogtreecommitdiff
path: root/drivers/clocksource
diff options
context:
space:
mode:
authorViresh Kumar <viresh.kumar@linaro.org>2013-08-31 17:48:23 +0530
committerMarek Szyprowski <m.szyprowski@samsung.com>2014-04-01 13:07:35 +0200
commitd4f7a025e14f89bf815855d72f4a905390cac624 (patch)
tree6796cfea07c2a094e6f00a6b9324916f16451880 /drivers/clocksource
parent56e69b35155ea6b699c6dba228aae5521fa8d4a2 (diff)
downloadlinux-3.10-d4f7a025e14f89bf815855d72f4a905390cac624.tar.gz
linux-3.10-d4f7a025e14f89bf815855d72f4a905390cac624.tar.bz2
linux-3.10-d4f7a025e14f89bf815855d72f4a905390cac624.zip
cpufreq: serialize calls to __cpufreq_governor()
We can't take a big lock around __cpufreq_governor() as this causes recursive locking for some cases. But calls to this routine must be serialized for every policy. Otherwise we can see some unpredictable events. For example, consider following scenario: __cpufreq_remove_dev() __cpufreq_governor(policy, CPUFREQ_GOV_STOP); policy->governor->governor(policy, CPUFREQ_GOV_STOP); cpufreq_governor_dbs() case CPUFREQ_GOV_STOP: mutex_destroy(&cpu_cdbs->timer_mutex) cpu_cdbs->cur_policy = NULL; <PREEMPT> store() __cpufreq_set_policy() __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); policy->governor->governor(policy, CPUFREQ_GOV_LIMITS); case CPUFREQ_GOV_LIMITS: mutex_lock(&cpu_cdbs->timer_mutex); <-- Warning (destroyed mutex) if (policy->max < cpu_cdbs->cur_policy->cur) <- cur_policy == NULL And so store() will eventually result in a crash if cur_policy is NULL at this point. Introduce an additional variable which would guarantee serialization here. Change-Id: Ibae767cbd9c25c7598b39d1405fa3d98d2125101 Reported-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/clocksource')
0 files changed, 0 insertions, 0 deletions