[ SOLVED ] Spectre and Meltdown Updates trash wifi

[apteryx]

Two problems:
1. I updated kernel to recommended 4.4.0.109 (from 3.16.0.48 ) this appears to
have trashed wifi. Now reports only operating at 1Mb/sec ( previously 144 Mb/sec )
i.e damn slow!!

Can I revert to old kernel or is there another driver that will restore wifi??
And a "how to" for the reccommended solution?

2. I updated the intel microcode to 3.20180108.0~ubuntu14.04.2
Now recommended to use 3.21080108.0+really20170707ubuntu14.04.1 BUT synaptic
does not allow "mark for install" when I try to check the box.

I did't try Force update. Should I??

SYSTEM INFO>>>>>>>>>>>>>>>>>>>

apteryx@megadyptes ~ $ inxi -Fzx
System: Host: megadyptes Kernel: 4.4.0-109-generic x86_64 (64 bit, gcc: 4.8.4)
Desktop: MATE 1.10.2 Distro: Linux Mint 17.2 Rafaela
Machine: Mobo: ASRock model: H81M-HDS R2.0 Bios: American Megatrends version: P1.10 date: 12/09/2014
CPU: Dual core Intel Core i3-4170 CPU (-HT-MCP-) cache: 3072 KB flags: (lm nx sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx) bmips: 14795.8
Clock Speeds: 1: 3700.00 MHz 2: 3700.00 MHz 3: 3699.855 MHz 4: 3700.00 MHz
Graphics: Card: Intel 4th Generation Core Processor Family Integrated Graphics Controller bus-ID: 00:02.0
X.Org: 1.15.1 drivers: intel (unloaded: fbdev,vesa) Resolution: 1920x1080@60.0hz
GLX Renderer: Mesa DRI Intel Haswell GLX Version: 3.0 Mesa 10.1.3 Direct Rendering: Yes
Audio: Card-1: Intel 8 Series/C220 Series High Definition Audio Controller driver: snd_hda_intel bus-ID: 00:1b.0
Card-2: Intel Xeon E3-1200 v3/4th Gen Core Processor HD Audio Controller driver: snd_hda_intel bus-ID: 00:03.0
Sound: Advanced Linux Sound Architecture ver: k4.4.0-109-generic
Network: Card-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
driver: r8169 ver: 2.3LK-NAPI port: e000 bus-ID: 02:00.0
IF: eth0 state: up speed: 100 Mbps duplex: full mac: <filter>
Card-2: Realtek RTL8192CU 802.11n WLAN Adapter driver: rtl8xxxu usb-ID: 003-004
IF: wlan1 state: up mac: <filter>
Drives: HDD Total Size: 1000.2GB (2.5% used) 1: id: /dev/sda model: WDC_WD10EZEX size: 1000.2GB
Partition: ID: / size: 909G used: 23G (3%) fs: ext4 ID: /boot size: 236M used: 172M (77%) fs: ext2
RAID: No RAID devices detected - /proc/mdstat and md_mod kernel raid module present
Sensors: System Temperatures: cpu: 37.0C mobo: N/A
Fan Speeds (in rpm): cpu: N/A
Info: Processes: 198 Uptime: 2:05 Memory: 721.4/7660.4MB Runlevel: 2 Gcc sys: 4.8.4
Client: Shell (bash 4.3.11) inxi: 1.9.17

apteryx@megadyptes ~ $ lsusb
Bus 002 Device 002: ID 8087:8000 Intel Corp.
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 006 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 005 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:8008 Intel Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 004: ID 0bda:8178 Realtek Semiconductor Corp. RTL8192CU 802.11n WLAN Adapter
Bus 003 Device 003: ID 046d:c31c Logitech, Inc. Keyboard K120 for Business
Bus 003 Device 002: ID 046d:c077 Logitech, Inc.
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

apteryx@megadyptes ~ $ lsmod |grep rtl
rtl8xxxu 73728 0
mac80211 733184 1 rtl8xxxu

apteryx@megadyptes ~ $ lspci -nnk | grep -iA2 net
02:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 11)
Subsystem: ASRock Incorporation Motherboard (one of many) [1849:8168]
Kernel driver in use: r8169

apteryx@megadyptes ~ $ rfkill list
1: phy1: Wireless LAN
Soft blocked: no
Hard blocked: no

apteryx@megadyptes ~ $ iwconfig
lo no wireless extensions.

wlan1 IEEE 802.11bgn ESSID:"XXXXXXXXXXXXX"
Mode:Managed Frequency:2.437 GHz Access Point: 00:66:64:E8:ED:C2
Bit Rate=1 Mb/s Tx-Power=20 dBm
Retry short limit:7 RTS thr=2347 B Fragment thr:off
Power Management:off
Link Quality=58/70 Signal level=-52 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:112 Missed beacon:0

eth0 no wireless extensions.

TIA

[apteryx]

UPDATE: Hmmm think this points to kernel ::

dmesg | grep 8192
[ 0.000000] PERCPU: Embedded 34 pages/cpu @ffff88021f200000 s99608 r8192 d31464 u524288
[ 0.000000] pcpu-alloc: s99608 r8192 d31464 u524288 alloc=1*2097152
[ 25.908929] usb 3-6: RTL8192CU rev A (TSMC) 2T2R, TX queues 2, WiFi=1, BT=0, GPS=0, HI PA=0
[ 25.908930] usb 3-6: RTL8192CU MAC: e827:07:e6:08
[ 25.908931] usb 3-6: rtl8xxxu: Loading firmware rtlwifi/rtl8192cufw_TMSC.bin
[ 26.868385] 8192cu: module verification failed: signature and/or required key missing - tainting kernel
[ 26.869089] usbcore: registered new interface driver rtl8192cu
[ 720.442463] usb 3-1: RTL8192CU rev A (TSMC) 2T2R, TX queues 2, WiFi=1, BT=0, GPS=0, HI PA=0
[ 720.442465] usb 3-1: RTL8192CU MAC: e827:07:e6:08
[ 720.442467] usb 3-1: rtl8xxxu: Loading firmware rtlwifi/rtl8192cufw_TMSC.bin

[michael louwe]

@ apteryx, .......

...

.
Access Grub menu, eg by repeatedly pressing the SHIFT or ESC key during startup. Select Advanced Options to boot from the previous stable kernel.

Once booted, go to >Update Manager >View >Linux kernels, to remove the unstable kernel.

[apteryx]

OK. Back on kernel 3.16.0.48. Wifi going normally.
So spectre and meltdown fixes all reversed out, apparently unfixable.
Intel is doomed.

Have installed noscript, and enforcing tight controls on all sites. Hopefully this will
provide some defence against attacks.
Thanks ml for reply.