linux-kernel - [PATCH v2 2/4] cpufreq: Init policy->rwsem before it may be possibly used

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Message-ID: <20250709104145.2348017-3-zhenglifeng1@huawei.com>
Date: Wed, 9 Jul 2025 18:41:43 +0800
From: Lifeng Zheng <zhenglifeng1@...wei.com>
To: <rafael@...nel.org>, <viresh.kumar@...aro.org>, <ionela.voinescu@....com>
CC: <linux-kernel@...r.kernel.org>, <linux-pm@...r.kernel.org>,
	<linuxarm@...wei.com>, <jonathan.cameron@...wei.com>,
	<zhanjie9@...ilicon.com>, <lihuisong@...wei.com>, <yubowen8@...wei.com>,
	<zhenglifeng1@...wei.com>
Subject: [PATCH v2 2/4] cpufreq: Init policy->rwsem before it may be possibly used

In cpufreq_policy_put_kobj(), policy->rwsem is used. But in
cpufreq_policy_alloc(), if freq_qos_add_notifier() returns an error, error
path via err_kobj_remove or err_min_qos_notifier will be reached and
cpufreq_policy_put_kobj() will be called before policy->rwsem is
initialized. Thus, the calling of init_rwsem() should be moved to where
before these two error paths can be reached.

Fixes: 67d874c3b2c6 ("cpufreq: Register notifiers with the PM QoS framework")
Signed-off-by: Lifeng Zheng <zhenglifeng1@...wei.com>
---
 drivers/cpufreq/cpufreq.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index eb713d116c34..2175d2df95b6 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1281,6 +1281,8 @@ static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
 		goto err_free_real_cpus;
 	}
 
+	init_rwsem(&policy->rwsem);
+
 	freq_constraints_init(&policy->constraints);
 
 	policy->nb_min.notifier_call = cpufreq_notifier_min;
@@ -1303,7 +1305,6 @@ static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
 	}
 
 	INIT_LIST_HEAD(&policy->policy_list);
-	init_rwsem(&policy->rwsem);
 	spin_lock_init(&policy->transition_lock);
 	init_waitqueue_head(&policy->transition_wait);
 	INIT_WORK(&policy->update, handle_update);
-- 
2.33.0