[PATCH] cpufreq: CPPC: Fix possible null-ptr-deref for cppc_get_cpu_cost()

From: Jinjie Ruan
Date: Wed Oct 30 2024 - 04:27:27 EST


cpufreq_cpu_get_raw() may return NULL if the cpu is not in
policy->cpus cpu mask and it will cause null pointer dereference,
so check NULL for cppc_get_cpu_cost().

Fixes: 740fcdc2c20e ("cpufreq: CPPC: Register EM based on efficiency class information")
Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
---
drivers/cpufreq/cppc_cpufreq.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 2b8708475ac7..67fa97bbeae7 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -487,6 +487,9 @@ static int cppc_get_cpu_cost(struct device *cpu_dev, unsigned long KHz,
int step;

policy = cpufreq_cpu_get_raw(cpu_dev->id);
+ if (!policy)
+ return 0;
+
cpu_data = policy->driver_data;
perf_caps = &cpu_data->perf_caps;
max_cap = arch_scale_cpu_capacity(cpu_dev->id);
--
2.34.1