From: Colin Ian King <colin.king@canonical.com>
Date: Tue, 5 Jan 2021 10:19:57 +0000 (+0000)
Subject: cpufreq: powernow-k8: pass policy rather than use cpufreq_cpu_get()
X-Git-Tag: accepted/tizen/unified/20230118.172025~8117^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=943bdd0cecad06da8392a33093230e30e501eccc;p=platform%2Fkernel%2Flinux-rpi.git

cpufreq: powernow-k8: pass policy rather than use cpufreq_cpu_get()

Currently there is an unlikely case where cpufreq_cpu_get() returns a
NULL policy and this will cause a NULL pointer dereference later on.

Fix this by passing the policy to transition_frequency_fidvid() from
the caller and hence eliminating the need for the cpufreq_cpu_get()
and cpufreq_cpu_put().

Thanks to Viresh Kumar for suggesting the fix.

Addresses-Coverity: ("Dereference null return")
Fixes: b43a7ffbf33b ("cpufreq: Notify all policy->cpus in cpufreq_notify_transition()")
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
index 0acc9e2..b9ccb6a 100644
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -878,9 +878,9 @@ static int get_transition_latency(struct powernow_k8_data *data)
 
 /* Take a frequency, and issue the fid/vid transition command */
 static int transition_frequency_fidvid(struct powernow_k8_data *data,
-		unsigned int index)
+		unsigned int index,
+		struct cpufreq_policy *policy)
 {
-	struct cpufreq_policy *policy;
 	u32 fid = 0;
 	u32 vid = 0;
 	int res;
@@ -912,9 +912,6 @@ static int transition_frequency_fidvid(struct powernow_k8_data *data,
 	freqs.old = find_khz_freq_from_fid(data->currfid);
 	freqs.new = find_khz_freq_from_fid(fid);
 
-	policy = cpufreq_cpu_get(smp_processor_id());
-	cpufreq_cpu_put(policy);
-
 	cpufreq_freq_transition_begin(policy, &freqs);
 	res = transition_fid_vid(data, fid, vid);
 	cpufreq_freq_transition_end(policy, &freqs, res);
@@ -969,7 +966,7 @@ static long powernowk8_target_fn(void *arg)
 
 	powernow_k8_acpi_pst_values(data, newstate);
 
-	ret = transition_frequency_fidvid(data, newstate);
+	ret = transition_frequency_fidvid(data, newstate, pol);
 
 	if (ret) {
 		pr_err("transition frequency failed\n");