linux-kernel - [PATCH] cpufreq: CPPC: Fix possible null-ptr-deref for cpufreq_cpu_get

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Message-ID: <20241030012019.357039-1-ruanjinjie@huawei.com>
Date: Wed, 30 Oct 2024 09:20:19 +0800
From: Jinjie Ruan <ruanjinjie@...wei.com>
To: <rafael@...nel.org>, <viresh.kumar@...aro.org>, <Pierre.Gondois@....com>,
	<linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC: <ruanjinjie@...wei.com>
Subject: [PATCH] cpufreq: CPPC: Fix possible null-ptr-deref for cpufreq_cpu_get_raw()

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

Fixes: 740fcdc2c20e ("cpufreq: CPPC: Register EM based on efficiency class information")
Signed-off-by: Jinjie Ruan <ruanjinjie@...wei.com>
---
 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..01c24c0ee9b3 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -420,6 +420,9 @@ static int cppc_get_cpu_power(struct device *cpu_dev,
 	struct cppc_cpudata *cpu_data;
 
 	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