Commit 873e919e3101 for kernel

commit 873e919e3101063a7a75989510ccfc125a4391cf
Author: Guenter Roeck <linux@roeck-us.net>
Date:   Thu May 14 14:41:00 2026 -0700

    hwmon: (lm90) Add lock protection to lm90_alert

    Sashiko reports:

    lm90_alert() executes in the smbus alert context and calls
    lm90_update_confreg() to disable the hardware alert line, without
    acquiring hwmon_lock.

    Concurrently, sysfs write operations (such as lm90_write_convrate) hold
    the hwmon_lock, temporarily modify data->config, and then restore it.

    If an alert interrupt occurs concurrently with a sysfs write, the sysfs
    path will overwrite the alert handler's modifications to data->config
    and the hardware register.

    This unintentionally re-enables the hardware alert line while the alarm is
    still active, causing an interrupt storm.

    Add the missing lock to lm90_alert() to solve the problem.

    Fixes: 7a1d220ccb0cc ("hwmon: (lm90) Introduce function to update configuration register")
    Reported-by: Sashiko <sashiko-bot@kernel.org>
    Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
index c4a9dafff81d..1eeb608e5903 100644
--- a/drivers/hwmon/lm90.c
+++ b/drivers/hwmon/lm90.c
@@ -2946,6 +2946,7 @@ static void lm90_alert(struct i2c_client *client, enum i2c_alert_protocol type,
 		 */
 		struct lm90_data *data = i2c_get_clientdata(client);

+		hwmon_lock(data->hwmon_dev);
 		if (!data->shutdown && (data->flags & LM90_HAVE_BROKEN_ALERT) &&
 		    (data->current_alarms & data->alert_alarms)) {
 			if (!(data->config & 0x80)) {
@@ -2955,6 +2956,7 @@ static void lm90_alert(struct i2c_client *client, enum i2c_alert_protocol type,
 			schedule_delayed_work(&data->alert_work,
 				max_t(int, HZ, msecs_to_jiffies(data->update_interval)));
 		}
+		hwmon_unlock(data->hwmon_dev);
 	} else {
 		dev_dbg(&client->dev, "Everything OK\n");
 	}