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hwmon: (lm90) Only report alarms if driver is ready

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Userspace can read sysfs attributes before driver registration is complete,
immediately after devm_hwmon_device_register_with_info() has been called.
At that time, data->hwmon_dev is not yet initialized. This can trigger
a NULL pointer access since lm90_update_device() and with it
lm90_update_alarms_locked() will be called. This call schedules
report_work and lm90_report_alarms(), which passes the still-NULL
data->hwmon_dev to hwmon_notify_event() and triggers a NULL pointer
dereference.

Fix the problem by only scheduling the report and alert workers
data->hwmon_dev is set.

Reported-by: Sashiko <sashiko-bot@kernel.org>
Fixes: f6d0775119 ("hwmon: (lm90) Rework alarm/status handling")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Guenter Roeck
2026-07-25 15:27:28 -07:00
parent f46d5ab43a
commit aa9429edf9
1 changed files with 2 additions and 2 deletions
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4
drivers/hwmon/lm90.c
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@@ -1194,7 +1194,7 @@ static int lm90_update_alarms_locked(struct lm90_data *data, bool force)
check_enable = (client->irq || !(data->config_orig & 0x80)) &&
(data->config & 0x80);
if (force || check_enable)
if (data->hwmon_dev && (force || check_enable))
schedule_work(&data->report_work);
/*
@@ -1202,7 +1202,7 @@ static int lm90_update_alarms_locked(struct lm90_data *data, bool force)
* alarms are all clear, and alerts are currently disabled.
* Otherwise (re)schedule worker if needed.
*/
if (check_enable) {
if (check_enable && data->hwmon_dev) {
if (!(data->current_alarms & data->alert_alarms)) {
dev_dbg(&client->dev, "Re-enabling ALERT#\n");
lm90_update_confreg(data, data->config & ~0x80);