From 389fbc3c8ad7c339cd2d9572d73c355b7b967823 Mon Sep 17 00:00:00 2001 Message-Id: <389fbc3c8ad7c339cd2d9572d73c355b7b967823.1379669625.git.viresh.kumar@linaro.org> From: Viresh Kumar Date: Fri, 20 Sep 2013 14:55:31 +0530 Subject: [PATCH] cpufreq: check cpufreq driver is valid and cpufreq isn't disabled in cpufreq_get() cpufreq_get() can be called from external drivers which might not be aware if cpufreq driver is registered or not. And so we should actually check if cpufreq driver is registered or not and also if cpufreq is active or disabled, at the beginning of cpufreq_get(). Otherwise call to lock_policy_rwsem_read() might hit BUG_ON(!policy). Signed-off-by: Viresh Kumar --- drivers/cpufreq/cpufreq.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 82ecbe3..db004a8 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1460,6 +1460,9 @@ unsigned int cpufreq_get(unsigned int cpu) { unsigned int ret_freq = 0; + if (cpufreq_disabled() || !cpufreq_driver) + return -ENOENT; + if (!down_read_trylock(&cpufreq_rwsem)) return 0; -- 1.7.12.rc2.18.g61b472e