Re: [appleir] BUG: unable to handle kernel NULL pointerdereference

From: Jiri Kosina
Date: Wed Nov 06 2013 - 12:03:57 EST


On Tue, 29 Oct 2013, Luis Henriques wrote:

> James has reported a NULL pointer dereference[1] on the appleir
> driver. From the bug report[2] it looks like it is 100%
> reproducible using a 3.12-rc6 kernel simply by pressing any button on
> the IR remote.
>
> >From the stack trace, it looks like input_event is invoked with the
> input_dev parameter set to NULL, which seems to indicate that
> appleir_input_configured is never invoked.
>
> Any ideas?
>
> [1] https://launchpadlibrarian.net/154942024/macmini-oops.jpg
> [2] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1244505

[ adding some more CCs ]

Okay, so apparently we didn't register with input, but only hiddev /
hidraw.

appleir 0003:05AC:8240.0005: hiddev0,hidraw4: USB HID v1.11 Device [Apple Computer, Inc. IR Receiver] on usb-0000:00:1d.3-2/input0

Therefore ->input_configured() callback has never been called, and thus we
oops due to appleir->input_dev being NULL when the first raw event is
reported.

Could you please provide report descriptor of the device?

The driver apparently relies on it being registered with hid-input, but
for some reason that doesn't happen.

--
Jiri Kosina
SUSE Labs
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