linux-kernel - [PATCH -next] cpufreq: CPPC: Fix wrong return value in cppc_get_cpu

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Message-ID: <20241106010111.2404387-1-ruanjinjie@huawei.com>
Date: Wed, 6 Nov 2024 09:01:11 +0800
From: Jinjie Ruan <ruanjinjie@...wei.com>
To: <rafael@...nel.org>, <viresh.kumar@...aro.org>, <ruanjinjie@...wei.com>,
	<linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC: <qperret@...gle.com>
Subject: [PATCH -next] cpufreq: CPPC: Fix wrong return value in cppc_get_cpu_power()

cppc_get_cpu_power() return 0 if the policy is NULL. Then in
em_create_perf_table(), the later zero check for power is not valid
as power is uninitialized. As Quentin pointed out, kernel energy model
core check the return value of active_power() first, so if the callback
failed it should tell the core. So return -EINVAL to fix it.

Fixes: a78e72075642 ("cpufreq: CPPC: Fix possible null-ptr-deref for cpufreq_cpu_get_raw()")
Signed-off-by: Jinjie Ruan <ruanjinjie@...wei.com>
Suggested-by: Quentin Perret <qperret@...gle.com>
---
 drivers/cpufreq/cppc_cpufreq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index cdc569cf7743..bd8f75accfa0 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -405,7 +405,7 @@ static int cppc_get_cpu_power(struct device *cpu_dev,
 
 	policy = cpufreq_cpu_get_raw(cpu_dev->id);
 	if (!policy)
-		return 0;
+		return -EINVAL;
 
 	cpu_data = policy->driver_data;
 	perf_caps = &cpu_data->perf_caps;
-- 
2.34.1