[PATCH v3] hwmon: nzxt-smart2: handle failure of devm_add_action in nzxt_smart2_hid_probe

From: void0red
Date: Mon Feb 27 2023 - 04:20:10 EST


From: Kang Chen <void0red@xxxxxxxxx>

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@xxxxxxxxxxxx
Signed-off-by: Kang Chen <void0red@xxxxxxxxx>
---
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