[PATCH 2/2] hwmon: (asus_rog_ryujin) Synchronize HID command and report handling

[Arie Miller]

rog_ryujin_execute_cmd() holds status_report_request_lock while
reinitializing a completion, intending to exclude raw-event handling.
However, rog_ryujin_raw_event() does not acquire the lock when it updates
the completion. A response can therefore race with reinit_completion() and
be lost, leaving the command to time out.

Hold the lock while parsing reports and updating their completions. Use the
irqsave variants in both paths because raw-event handling may run in
interrupt context.

Fixes: ed3e03790c5c ("hwmon: Add driver for ASUS ROG RYUJIN II 360 AIO cooler")
Reported-by: Sashiko <sashiko-bot@xxxxxxxxxx>
Closes: https://lore.kernel.org/linux-hwmon/20260812104617.858D01F000E9@xxxxxxxxxxxxxxx/
Cc: stable@xxxxxxxxxxxxxxx
Assisted-by: Codex:gpt-5.6-sol sparse
Signed-off-by: Arie Miller <renari@xxxxxxxxxx>
---
 drivers/hwmon/asus_rog_ryujin.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/hwmon/asus_rog_ryujin.c b/drivers/hwmon/asus_rog_ryujin.c
index f4d99c510369..e297557ca346 100644
--- a/drivers/hwmon/asus_rog_ryujin.c
+++ b/drivers/hwmon/asus_rog_ryujin.c
@@ -184,6 +184,7 @@ static int rog_ryujin_write_expanded(struct rog_ryujin_data *priv, const u8 *cmd
 static int rog_ryujin_execute_cmd(struct rog_ryujin_data *priv, const u8 *cmd, int cmd_length,
 				  struct completion *status_completion)
 {
+	unsigned long flags;
 	int ret;
 
 	/*
@@ -191,9 +192,9 @@ static int rog_ryujin_execute_cmd(struct rog_ryujin_data *priv, const u8 *cmd, i
 	 * completion. Reinit is done because hidraw could have triggered
 	 * the raw event parsing and marked the passed in completion as done.
 	 */
-	spin_lock_bh(&priv->status_report_request_lock);
+	spin_lock_irqsave(&priv->status_report_request_lock, flags);
 	reinit_completion(status_completion);
-	spin_unlock_bh(&priv->status_report_request_lock);
+	spin_unlock_irqrestore(&priv->status_report_request_lock, flags);
 
 	/* Send command for getting data */
 	ret = rog_ryujin_write_expanded(priv, cmd, cmd_length);
@@ -421,15 +422,18 @@ static int rog_ryujin_raw_event(struct hid_device *hdev, struct hid_report *repo
 				int size)
 {
 	struct rog_ryujin_data *priv = hid_get_drvdata(hdev);
+	unsigned long flags;
 
 	if (size < 2 || data[0] != RYUJIN_CMD_PREFIX)
 		return 0;
 
+	spin_lock_irqsave(&priv->status_report_request_lock, flags);
+
 	if (data[1] == RYUJIN_GET_COOLER_STATUS_CMD_RESPONSE) {
 		if (size <= priv->info->temp_offset + 1 ||
 		    size <= priv->info->pump_speed_offset + 1 ||
 		    size <= priv->info->fan_speed_offset + 1)
-			return 0;
+			goto unlock;
 
 		/* Received coolant temp and speeds of pump and internal fan */
 		priv->temp_input[0] = data[priv->info->temp_offset] * 1000 +
@@ -443,7 +447,7 @@ static int rog_ryujin_raw_event(struct hid_device *hdev, struct hid_report *repo
 			complete_all(&priv->cooler_status_received);
 	} else if (data[1] == RYUJIN_GET_CONTROLLER_SPEED_CMD_RESPONSE) {
 		if (size <= RYUJIN_CONTROLLER_SPEED_3 + 1)
-			return 0;
+			goto unlock;
 
 		/* Received speeds of four fans attached to the controller */
 		priv->speed_input[2] = get_unaligned_le16(data + RYUJIN_CONTROLLER_SPEED_1);
@@ -455,7 +459,7 @@ static int rog_ryujin_raw_event(struct hid_device *hdev, struct hid_report *repo
 			complete_all(&priv->controller_status_received);
 	} else if (data[1] == RYUJIN_GET_COOLER_DUTY_CMD_RESPONSE) {
 		if (size <= RYUJIN_INTERNAL_FAN_DUTY)
-			return 0;
+			goto unlock;
 
 		/* Received report for pump and internal fan duties (in %) */
 		if (data[RYUJIN_PUMP_DUTY] == 0 && data[RYUJIN_INTERNAL_FAN_DUTY] == 0) {
@@ -474,7 +478,7 @@ static int rog_ryujin_raw_event(struct hid_device *hdev, struct hid_report *repo
 				 * We're expecting a report, so parse it.
 				 */
 				goto read_cooler_duty;
-			return 0;
+			goto unlock;
 		}
 read_cooler_duty:
 		priv->duty_input[0] = rog_ryujin_percent_to_pwm(data[RYUJIN_PUMP_DUTY]);
@@ -484,7 +488,7 @@ static int rog_ryujin_raw_event(struct hid_device *hdev, struct hid_report *repo
 			complete_all(&priv->cooler_duty_received);
 	} else if (data[1] == RYUJIN_GET_CONTROLLER_DUTY_CMD_RESPONSE) {
 		if (size <= RYUJIN_CONTROLLER_DUTY)
-			return 0;
+			goto unlock;
 
 		/* Received report for controller duty for fans (in PWM) */
 		if (data[RYUJIN_CONTROLLER_DUTY] == 0) {
@@ -503,7 +507,7 @@ static int rog_ryujin_raw_event(struct hid_device *hdev, struct hid_report *repo
 				 * We're expecting a report, so parse it.
 				 */
 				goto read_controller_duty;
-			return 0;
+			goto unlock;
 		}
 read_controller_duty:
 		priv->duty_input[2] = data[RYUJIN_CONTROLLER_DUTY];
@@ -512,6 +516,8 @@ static int rog_ryujin_raw_event(struct hid_device *hdev, struct hid_report *repo
 			complete_all(&priv->controller_duty_received);
 	}
 
+unlock:
+	spin_unlock_irqrestore(&priv->status_report_request_lock, flags);
 	return 0;
 }
 
-- 
2.55.0