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cpufreq: scmi: Fix possible null pointer dereference

PATCH In review Chenyuan Yang 2 participants 3 messages Apr 12, 2025

Subsystems (2)
CPU frequency scaling framework System control & power/management interface (SCPI/SCMI) Message Protocol drivers
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Chenyuan Yang

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#0 lore raw

PATCH 1/1 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 <[email protected]>
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(-)
drivers/cpufreq/scmi-cpufreq.c +5 -1
index c310aeebc8f3..ee916ce9b897 100644
@@ -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;
Signature · 1 line
2.34.1
#1 lore raw
Quoted 9 lines · Chenyuan Yang

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 <[email protected]>
Fixes 99d6bdf33877 ("cpufreq: add support for CPU DVFS based on SCMI message protocol")

Henry Martin already fixed this in commit 484d3f15cc6c ("cpufreq: scmi:
Fix null-ptr-deref in scmi_cpufreq_get_rate()").

regards,
dan carpenter

author
#2 lore raw
Quoted 7 lines · Dan Carpenter
Quoted 5 lines · Chenyuan Yang

Check if policy is NULL before dereferencing it.

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

Quoted 7 lines
Quoted 4 lines

This is found by our static analysis tool KNighter.

Signed-off-by Chenyuan Yang <[email protected]>
Fixes 99d6bdf33877 ("cpufreq: add support for CPU DVFS based on SCMI message protocol")

Henry Martin already fixed this in commit 484d3f15cc6c ("cpufreq: scmi:
Fix null-ptr-deref in scmi_cpufreq_get_rate()").

Thanks so much for pointing this out!
It is good to hear that there is already a fix.

Quoted 2 lines

regards,
dan carpenter

-Chenyuan