cpufreq: fix null object access on Transmeta CPU

If cpu specific cpufreq driver(i.e.  longrun) has "setpolicy" function,
governor object isn't set into cpufreq_policy object at "__cpufreq_set_policy"
function in driver/cpufreq/cpufreq.c .

This causes a null object access at "store_scaling_setspeed" and
"show_scaling_setspeed" function in driver/cpufreq/cpufreq.c when reading or
writing through /sys interface (ex.  cat
/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed)

Addresses:
	http://bugzilla.kernel.org/show_bug.cgi?id=10654
	https://bugzilla.redhat.com/show_bug.cgi?id=443354

Signed-off-by: CHIKAMA Masaki <masaki.chikama@gmail.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Chuck Ebbert <cebbert@redhat.com>
Acked-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 86f0a24..4e07d1f 100644 (file)
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -625,7 +625,7 @@ static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
        unsigned int freq = 0;
        unsigned int ret;
 
-       if (!policy->governor->store_setspeed)
+       if (!policy->governor || !policy->governor->store_setspeed)
                return -EINVAL;
 
        ret = sscanf(buf, "%u", &freq);
@@ -639,7 +639,7 @@ static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
 
 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
 {
-       if (!policy->governor->show_setspeed)
+       if (!policy->governor || !policy->governor->show_setspeed)
                return sprintf(buf, "<unsupported>\n");
 
        return policy->governor->show_setspeed(policy, buf);