linux-kernel - [PATCH V3 1/4] cpufreq: cppc: Fix potential memleak in cppc_cpufreq_cpu

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Date:   Mon, 21 Jun 2021 14:49:34 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Rafael Wysocki <rjw@...ysocki.net>,
        Ionela Voinescu <ionela.voinescu@....com>,
        Viresh Kumar <viresh.kumar@...aro.org>
Cc:     linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Qian Cai <quic_qiancai@...cinc.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH V3 1/4] cpufreq: cppc: Fix potential memleak in cppc_cpufreq_cpu_init

It's a classic example of memleak, we allocate something, we fail and
never free the resources.

Make sure we free all resources on policy ->init() failures.

Fixes: a28b2bfc099c ("cppc_cpufreq: replace per-cpu data array with a list")
Tested-by: Vincent Guittot <vincent.guittot@...aro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 drivers/cpufreq/cppc_cpufreq.c | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index be4f62e2c5f1..35b8ae66d1fb 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -256,6 +256,16 @@ static struct cppc_cpudata *cppc_cpufreq_get_cpu_data(unsigned int cpu)
 	return NULL;
 }
 
+static void cppc_cpufreq_put_cpu_data(struct cpufreq_policy *policy)
+{
+	struct cppc_cpudata *cpu_data = policy->driver_data;
+
+	list_del(&cpu_data->node);
+	free_cpumask_var(cpu_data->shared_cpu_map);
+	kfree(cpu_data);
+	policy->driver_data = NULL;
+}
+
 static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 {
 	unsigned int cpu = policy->cpu;
@@ -309,7 +319,8 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	default:
 		pr_debug("Unsupported CPU co-ord type: %d\n",
 			 policy->shared_type);
-		return -EFAULT;
+		ret = -EFAULT;
+		goto out;
 	}
 
 	/*
@@ -324,10 +335,14 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	cpu_data->perf_ctrls.desired_perf =  caps->highest_perf;
 
 	ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls);
-	if (ret)
-		pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
-			 caps->highest_perf, cpu, ret);
+	if (!ret)
+		return 0;
 
+	pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
+		 caps->highest_perf, cpu, ret);
+
+out:
+	cppc_cpufreq_put_cpu_data(policy);
 	return ret;
 }
 
@@ -345,12 +360,7 @@ static int cppc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 		pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
 			 caps->lowest_perf, cpu, ret);
 
-	/* Remove CPU node from list and free driver data for policy */
-	free_cpumask_var(cpu_data->shared_cpu_map);
-	list_del(&cpu_data->node);
-	kfree(policy->driver_data);
-	policy->driver_data = NULL;
-
+	cppc_cpufreq_put_cpu_data(policy);
 	return 0;
 }
 
-- 
2.31.1.272.g89b43f80a514