Kernel panic on stable kernel 3.8.2 when closing bluetooth dun connection

Hi,

This is just a short note to let you know that 3.8.2 panics on closing a bluetooth dun connection.

This is seen with the ubuntu mainline kernel 3.8.2 that should be a vanilla stable kernel.

Observed on a DELL E6500 which has BCM2046 Bluetooth while connecting to the
internet using a Samsung Galaxy S mobile phone via bluetooth DUN through the network manager. When network manager is asked to close the connection, the kernel panics, the system drops out of Xorg, shows for a couple of seconds a long log including the words 'panic' and 'not synching', the numlock, caps-lock keys start flashing and the system freezes.

It is 100% repeatable.

The ubuntu kernel, that is a 3.5.0 plus ubuntu tweaks, backports, etc does not panic.

Thanks for the attention and best regards,

Sergio Callegari

Have you notified the linux bluetooth developers about this? Is this new in 3.8.2 and 3.8.1 or 3.8 works fine?

thanks,

greg k-h

Hi, thanks for the advice.

I have verified that the issue was introduced with 3.8.0 and is not due to stabilization patches in the 3.8.x series. 3.7.x is fine (from x=0 to x=8) Sorry for not having checked earlier, but I was incorrectly taken for granted that if the bug was back in 3.8.0 someone would have noticed already... Now notifying the bluetooth developers too.

Sergio

Hi,

This is just a short note to let you know that 3.8.x panics on closing a bluetooth dun connection.

This is seen with the ubuntu /mainline/ kernel 3.8.0 and 3.8.2 that should vanilla kernels with no ubuntu tweaking.

Observed on a DELL E6500 which has BCM2046 Bluetooth while connecting to the
internet using a Samsung Galaxy S mobile phone via bluetooth DUN through the network manager. When network manager is asked to close the connection, the kernel panics, the system drops out of Xorg, shows for a couple of seconds a long log including the words 'panic' and 'not synching', the numlock, caps-lock keys start flashing and the system freezes.

It is 100% repeatable.

kernels 3.7.0 and 3.7.8 do not panic.

Thanks for the attention and best regards,

Sergio Callegari

In the end it may not be caused by bluetooth, but by ppp.

Found bug reports on ubuntu indicating that 3.8.x panic on ppp disconnection. Unfortunately, I cannot try without bluetooth with my configuration. (when wired, phone does not use ppp, but appears as a wired network interface).

Sergio

Hi,

I'm following up with a previous email where I was reporting a systematic kernel panic when closing a bluetooth DUN connection.

I have made a few more tests:

- Bug happens with all the 3.8.x kernel series, up to the latest 3.8.6
- Bug is not present up to 3.7.x, including the latest 3.7.10
- Bug happens on the DELL E6500 laptop that has a Dell Computer Corp. Wireless 370 Bluetooth Mini-card
- Bug also happens on a desktop that has a Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)

Let me recall that the bug is triggered by connecting to the internet via a mobile phone, using bluetooth DUN and then disconnecting. Kernel panics on disconnection (the phone I am using is a Samsung Galaxy S Plus)

- Bug does not happen on the same machines when connecting to the internet via ppp using a usb-umts dongle

Hope this can helps haunting the regression.

Thanks for the attention,

Sergio

Hi,

I'm following up with a previous email where I was reporting a systematic kernel panic/system freeze when closing a bluetooth DUN connection.

I have made a few more tests, all with 64 bit machines:

- Bug happens with all the 3.8.x kernel series, up to the latest 3.8.6
- Bug happens with the 3.9RC6 kernel
- Bug is not present up to 3.7.x, including the latest 3.7.10
- Bug happens on the DELL E6500 laptop that has a Dell Computer Corp. Wireless 370 Bluetooth Mini-card
- Bug also happens on a desktop that has a Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)

Let me recall that the bug is triggered by connecting to the internet via a mobile phone, using bluetooth DUN and then disconnecting. Kernel panics on disconnection (the phone I am using is a Samsung Galaxy S Plus)

- Bug does not happen on the same machines when connecting to the internet via ppp using a usb gsm/umts dongle and the same provider, so the bug seems to be BT related and not common to all internet connections using a Point to Point serial protocol.

Unfortunately, I see the bug on a machine that I use for day by day work and I cannot afford bisecting here.

Nonetheless, the bug seems easy to reproduce (I catched it on two different machines with different setups). So I hope this note can help haunting the regression anyway.

Thanks for the attention,

Sergio Callegari