From:   void0red <void0red@gmail.com>
To:     linux@roeck-us.net
Cc:     jdelvare@suse.com, linux-hwmon@vger.kernel.org,
        linux-kernel@vger.kernel.org, mezin.alexander@gmail.com,
        void0red@gmail.com
Subject: [PATCH v3] hwmon: nzxt-smart2: handle failure of devm_add_action in nzxt_smart2_hid_probe
Date:   Mon, 27 Feb 2023 17:15:34 +0800
Message-Id: <20230227091534.907101-1-void0red@gmail.com>
In-Reply-To: <f5043281-9b3e-e454-16fe-ef4cde36dfdb@roeck-us.net>
References: <f5043281-9b3e-e454-16fe-ef4cde36dfdb@roeck-us.net>
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From: Kang Chen <void0red@gmail.com>

1. replace the devm_add_action with devm_add_action_or_reset to ensure
the mutex lock can be destroyed when it fails.
2. use local wrapper function mutex_fini instead of mutex_destroy to
avoid undefined behaviours.
3. add a check of devm_add_action_or_reset and return early when it fails.

Link: https://lore.kernel.org/all/f5043281-9b3e-e454-16fe-ef4cde36dfdb@roeck-us.net
Signed-off-by: Kang Chen <void0red@gmail.com>
---
v3 -> v2: use local function and devm_add_action_or_rest
v2 -> v1: split the patch

 drivers/hwmon/nzxt-smart2.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/nzxt-smart2.c b/drivers/hwmon/nzxt-smart2.c
index 2b93ba896..340002581 100644
--- a/drivers/hwmon/nzxt-smart2.c
+++ b/drivers/hwmon/nzxt-smart2.c
@@ -721,6 +721,11 @@ static int __maybe_unused nzxt_smart2_hid_reset_resume(struct hid_device *hdev)
 	return init_device(drvdata, drvdata->update_interval);
 }
 
+static void mutex_fini(void *lock)
+{
+	mutex_destroy(lock);
+}
+
 static int nzxt_smart2_hid_probe(struct hid_device *hdev,
 				 const struct hid_device_id *id)
 {
@@ -737,8 +742,9 @@ static int nzxt_smart2_hid_probe(struct hid_device *hdev,
 	init_waitqueue_head(&drvdata->wq);
 
 	mutex_init(&drvdata->mutex);
-	devm_add_action(&hdev->dev, (void (*)(void *))mutex_destroy,
-			&drvdata->mutex);
+	ret = devm_add_action_or_reset(&hdev->dev, mutex_fini, &drvdata->mutex);
+	if (ret)
+		return ret;
 
 	ret = hid_parse(hdev);
 	if (ret)
-- 
2.34.1