Kernel Bug Tracker – Bug 51201
Kernel crashes at snd_usbmidi_output_close() when device is removed
Last modified: 2013-11-13 17:28:31 UTC
Created attachment 88041 [details]
Kernel OOPS message
There's something wrong at snd_usbmidi_output_close(). When using gdigi with a Digitech RP-255 pedal, sometimes I disconnect the pedal before closing gdigi.
When gdigi is later closed, Kernel panics at snd_usbmidi_output_close(). I suspect that there are some missing tests there, to see if the device's data
are still there.
The end result is a Kernel panic:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000190
IP: [<ffffffff8143fb54>] usb_autopm_put_interface+0x14/0x40
[<ffffffffa078f809>] snd_usbmidi_output_close+0x29/0x40 [snd_usbmidi_lib]
I'm attaching the full OOPS message, and the lsusb -v info of the device.
Created attachment 88051 [details]
lsusb for DigiTech RP255 Guitar Multi-Effects Processor
The patches below should fix the issue. Please try them out.
These were merged in sound git tree for-next branch, too.
Created attachment 88381 [details]
Created attachment 88391 [details]
A patch referencing this bug report has been merged in Linux v3.8-rc1:
Author: Takashi Iwai <email@example.com>
Date: Mon Dec 3 11:12:46 2012 +0100
ALSA: usb-audio: Avoid autopm calls after disconnection