vmlinuz-4.4.0-63-generic kernel crashes with Realtex RTL8192CU 802.11n WLAN Adapter

[alain williams]

Inserting this USB Wifi dongle causes the machine to crash, if inserted when booting it will crash when the desktop starts up (before login).

This does not happen with the previous kernel: 4.4.0-62 - if I boot that one the machine and Wifi works; OK it is not reliable and suffers occasional outages - ie need to disconnect/reconnect.

This is repeatable - happens every time.

mint 18.1 - 64 bit. Intel celeron N2840.

I am aware that Realtex has a very bad smell about it; but the machine should not crash.
The adapter is packaged by Edimax n300 (EW-7722UTn V2). lsusb tells me:

ID 0bda:8178 Realtex Semiconductor Corp. RTL8192CU 802.11n WLAN Adapter

Looking at the console I see:

BUG unable to handle kernel NULL pointer dereference at 0000000048
IP: <...> rtl_lps_leave+0x17/0x50 [rtlwifi]

I have attached a (not very good) image of the console; I'll try to attach a second one that shows a bit more.

[alain williams (addw)]

The other screen shot.

[alain williams (addw)]

I have just installed kernel 4.4.0-64-generic - it still crashes when the dongle is plugged in.

[Christian Laboranowitsch (chvistian)]

Same problem with me: lsusb gives:
ASUSTek Computer, Inc. N10 Nano 802.11n Network Adapter [Realtek RTL8192CU]
Made the same observation like Alain. Directly crashing after boot. 4.4.0-62 does not show the problem.
Haven't tried 4.4.0-64
mint 18.1 - 64 bit Acer Aspire

[alain williams (addw)]

Earlier today I sent an email to <email address hidden>, I have received an automated reply that promises a reply within 24 hours. I have not received anything from a human -- yet. Curiously there is not a ticket number!

[alain williams (addw)]

I have a reply from Edimax, see below along with my reply:

On Thu, Feb 23, 2017 at 04:36:41PM +0100, Support Edimax Europe BV wrote:
> Dear Alain Williams,
>
> We need to forward your inquiry to our headquarters.
> Perhaps they can give more information after they read your bug report.
>
> For further questions, please feel free to contact our technical support at: <email address hidden>, or > at the telephone number below. If we do not receive any reply from the end-user within 5 business > days with regards to the last inquiry, we assume that the case is closed.

It is still a problem. I am also in touch with someone else who experiences the
same problem, but on a different computer than I have been using. My machines
are 5-6 year old Dells [ desktop PCs ] (I'll find & give you the exact model if
you want to know) and an HP Stream laptop (about 15 months old).

Thanks

[Christian Laboranowitsch (chvistian)]

Not so promising. But let's see what is coming from that side...

Cheers
Christian

[alain williams (addw)]

Quick fix is to ensure than the 4.4.0-62 is run, ie not a later one.

All needs to be done as root.

Edit: /etc/default/grub

Near the top find the line:
GRUB_DEFAULT=0

Replace by:
GRUB_DEFAULT='Advanced options for Linux Mint 18 MATE 64-bit>Linux Mint 18 MATE 64-bit, with Linux 4.4.0-62-generic'

Run the command:
update-grub

[Frans Ketelaars (frans-2)]

kernel 4.4.0-63 with USB WLAN RTL8192CU freezes desktop

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1666421

status: In Progress → Fix Committed

[Frans Ketelaars (frans-2)]

Running Mint 18.1, latest kernel 4.8.0-41-generic

lsusb:
Bus 001 Device 006: ID 0b05:17ba ASUSTek Computer, Inc. N10 Nano 802.11n Network Adapter [Realtek RTL8192CU]

Inserting the device goes OK but the system freezes when trying to connect.

After reading https://bugzilla.redhat.com/show_bug.cgi?id=1421385 I blacklisted the rtl8192cu driver, inserting the device and connecting now works :)

lsmod:
rtl8xxxu 122880 0
mac80211 761856 1 rtl8xxxu
cfg80211 581632 1 mac80211

[Christian Laboranowitsch (chvistian)]

Hi there,

according to

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1666421

the issue seems to persist even in 4.4.0-67, so guess I have to stay on 4.4.0-62.

[Frans Ketelaars (frans-2)]

Running Mint 18.1, latest kernel 4.8.0-49-generic, the rtl8192cu driver
now works, WiFi much better then with my workaround in comment #10 :)

[Frans Ketelaars (frans-2)]

Kernel 4.8.0-51-generic also works.

[Frans Ketelaars (frans-2)]

Kernel 4.4.0-77-generic also works.

The Ubuntu bug https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1687623 with this kernel update was solved according to comment #36 .

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.