[PATCH 6.1.y] cpufreq: amd-pstate: add check for cpufreq_cpu_get's return value

[jianqi.ren.cn]

From: Anastasia Belova <abelova@xxxxxxxxxxxxx>

[ Upstream commit 5493f9714e4cdaf0ee7cec15899a231400cb1a9f ]

cpufreq_cpu_get may return NULL. To avoid NULL-dereference check it
and return in case of error.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Anastasia Belova <abelova@xxxxxxxxxxxxx>
Reviewed-by: Perry Yuan <perry.yuan@xxxxxxx>
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Signed-off-by: Jianqi Ren <jianqi.ren.cn@xxxxxxxxxxxxx>
---
 drivers/cpufreq/amd-pstate.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 90dcf26f0973..106aef210003 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -309,9 +309,14 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
 	unsigned long max_perf, min_perf, des_perf,
 		      cap_perf, lowest_nonlinear_perf, max_freq;
 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
-	struct amd_cpudata *cpudata = policy->driver_data;
+	struct amd_cpudata *cpudata;
 	unsigned int target_freq;
 
+	if (!policy)
+		return;
+
+	cpudata = policy->driver_data;
+
 	cap_perf = READ_ONCE(cpudata->highest_perf);
 	lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf);
 	max_freq = READ_ONCE(cpudata->max_freq);
-- 
2.25.1