Comment 10 for bug 1836809

Created attachment 283773
callstacks

Hello everyone,

We are currently developing a device that contains two HID services.
That device, as it is right now, is properly functioning on Windows & Android.
However, when pairing the device on Linux running bluez 5.50 we do get segfaults (see attached files).
Our bluetooth device has 4 services : 1 battery service, 2 HID Over Gatt services and 1 device information service.
With trial and error, we managed to find that we wouldn't get any crash as long as only 1 HOG service was present.

Here's the interesting part. The two HOG services are made as follows:
- standard keyboard over gatt: protocole mode / report map / 1 INPUT report / boot INPUT + OUTPUT / HID information / HID Control point
- raw HID over gatt : report map / 1 INPUT report / 1 OUTPUT report / HID information / HID control point

Looking at the write_ccc in the call stacks we wondered if the callbacks subscribing to notifications for the INPUT reports were causing this issue.

We therefore changed the raw HID over gatt (and its report map) to remove the INPUT report and change it into 1 OUTPUT report (leading to 2 OUTPUT reports): no crash.

We therefore hypothesize that the segfault occurs when subscribing to notification on a second HOG service..