linux-kernel - [PATCH] cpufreq: scmi: Fix possible null pointer dereference

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Message-Id: <20250412180831.3252963-1-chenyuan0y@gmail.com>
Date: Sat, 12 Apr 2025 13:08:31 -0500
From: Chenyuan Yang <chenyuan0y@...il.com>
To: sudeep.holla@....com,
	cristian.marussi@....com,
	rafael@...nel.org,
	viresh.kumar@...aro.org
Cc: arm-scmi@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Chenyuan Yang <chenyuan0y@...il.com>
Subject: [PATCH] cpufreq: scmi: Fix possible null pointer dereference

Check if policy is NULL before dereferencing it.

This is similar to the commit cf7de25878a1
("cppc_cpufreq: Fix possible null pointer dereference").

This is found by our static analysis tool KNighter.

Signed-off-by: Chenyuan Yang <chenyuan0y@...il.com>
Fixes: 99d6bdf33877 ("cpufreq: add support for CPU DVFS based on SCMI message protocol")
---
 drivers/cpufreq/scmi-cpufreq.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c
index c310aeebc8f3..ee916ce9b897 100644
--- a/drivers/cpufreq/scmi-cpufreq.c
+++ b/drivers/cpufreq/scmi-cpufreq.c
@@ -38,10 +38,14 @@ static struct cpufreq_driver scmi_cpufreq_driver;
 static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
 {
 	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
-	struct scmi_data *priv = policy->driver_data;
+	struct scmi_data *priv;
 	unsigned long rate;
 	int ret;
 
+	if (!policy)
+		return 0;
+	priv = policy->driver_data;
+
 	ret = perf_ops->freq_get(ph, priv->domain_id, &rate, false);
 	if (ret)
 		return 0;
-- 
2.34.1