# \[PATCH\] HID: wacom: check input\_dev-\>absinfo in wacom\_bpt3\_touch\_msg

- From: Yiyuan GUO \<hidden\>
- Date: 2021-05-17 09:34:30 
- List: linux-input
- Page: https://ratatoskr.run/linux-input/2021/05/8933010
- Thread: https://ratatoskr.run/linux-input/2021/05/8933010/t.md

```text
The function wacom_bpt3_touch_msg calls input_abs_get_res(input,
ABS_MT_POSITION_X) to obtain x_res, which may equal to 0 if
input->absinfo is NULL. Since x_res is used as a divisor, this
may lead to divide by zero problem.

Signed-off-by: Yiyuan GUO <redacted>
---
 drivers/hid/wacom_wac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index 81d7d12bc..a5a6fb8bc 100644
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -2892,7 +2892,7 @@ static void wacom_bpt3_touch_msg(struct wacom_wac *wacom, unsigned char *data)
 	bool touch = data[1] & 0x80;
 	int slot = input_mt_get_slot_by_key(input, data[0]);
 
-	if (slot < 0)
+	if (slot < 0 || !input->absinfo)
 		return;
 
 	touch = touch && report_touch_events(wacom);
-- 
2.25.1

```