The `input_mt_get_slot_by_key` function may return a negative value
if an error occurs (e.g. running out of slots). If this occurs we
should really avoid reporting any data for the slot.

Signed-off-by: Ping Cheng <ping.cheng@wacom.com>
Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
---
 drivers/hid/wacom_wac.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index 27587070a192..ce9e8e9b48b6 100644
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c

@@ -2551,6 +2551,9 @@ static void wacom_wac_finger_slot(struct wacom_wac *wacom_wac,
 		int slot;
 
 		slot = input_mt_get_slot_by_key(input, hid_data->id);
+		if (slot < 0)
+			return;
+
 		input_mt_slot(input, slot);
 		input_mt_report_slot_state(input, MT_TOOL_FINGER, prox);
 	}

-- 
2.32.0