Kernel panic when plugging in USB Wifi USB adapter

[Bernhard G]

Since updating my Lubuntu 16.10 system (linux-image-4.8.0-37-generic to linux-image-4.8.0-38-generic) the kernel panics as soon as I plug in the Wifi adapter (Edimax EW-7612UAn Wifi USB Adapter).
The coredump logs
BUG: unable to handle kernel NULL pointer dereference @0000000000000048
IP: [<ffffffffc0786647>] rtl_lps_leave+0x17/0x50 [rtlwifi]
PGD 0
Ooops: 0000 [#1] SMP
This is followed by the Modules linked in, Hardware info, Stack trace.
At the end of the trace it says:
Kernel panic - not syncing: Fatal exception in interrupt.

I uploaded a console screenshot here: IMG_20170222_230239.jpg
and I didn't find anything suspicious in syslog or kernel log, most probably because the kernel panics almost instantly after plugging the usb adapter in.

Updating to linux-image-4.8.0-39-generic does not solve the issue as well.

Only way to work around the issue is to select the 4.8.0-37 image from the grub bootmenu.
The problem is not related to a specific USB port.

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1669815

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Manfred Hampl (m-hampl)]

Probably a duplicate of Bug #1666421

[Joseph Salisbury (jsalisbury)]

Can you test the kernel located here:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1666421/comments/7

[Bernhard G (bernhard001-gmx)]

I installed the kernel 4.4.0 provided by jsalisbury. This works for me:

$ uname -a
Linux media-desktop 4.4.0-64-generic #85~lp1666421 SMP Wed Feb 22 21:37:35 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

$ lsusb | grep "Edimax"
Bus 001 Device 002: ID 7392:7822 Edimax Technology Co., Ltd

$ ifconfig wlx74da3894b952
wlx74da3894b952: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
        inet 192.168.1.52 netmask 255.255.255.0 broadcast 192.168.1.255
        ether 74:da:38:94:b9:52 txqueuelen 1000 (Ethernet)
        RX packets 3327 bytes 2122333 (2.1 MB)
        RX errors 0 dropped 0 overruns 0 frame 0
        TX packets 2755 bytes 370569 (370.5 KB)
        TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

I don't know much about the different kernel versions. Would It be possible to apply the modification to the 4.8.0 kernel as well, so I can test that, too?

I tested
 * booting without device attached, then attaching it after boot.
 * booting with device attached.
Both works fine. Should I test anything else?