iwlwifi regression in artful - intermittent total packet loss

[Max Bowsher]

Recently I have been experiencing intermitted total packet loss over wifi.

I've already been looking at another issue in which Bluetooth coexistence seems to be causing controller hardware to crash - bug 1719210 - so I'm rather suspicious of the updated iwlwifi microcode that is used by newer kernel versions.

Unfortunately, I don't have a good reproduction recipe, as the fault doesn't seem to occur immediately after boot, nor is it an absolute failure of connectivity - from a user perspective, it feels like, for example, the website you are using is responding exceptionally slowly. It is only on testing multiple remote sites, and finding that rebooting into an earlier kernel fixes the issue, that it is apparent that it's a local OS problem.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: linux-image-4.13.0-12-generic 4.13.0-12.13
ProcVersionSignature: Ubuntu 4.13.0-12.13-generic 4.13.3
Uname: Linux 4.13.0-12-generic x86_64
ApportVersion: 2.20.7-0ubuntu2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: maxb 1859 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
Date: Sun Oct 8 19:10:31 2017
EcryptfsInUse: Yes
HibernationDevice: RESUME=UUID=635db8ca-b352-4622-87eb-08f74460324b
InstallationDate: Installed on 2016-08-16 (418 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
MachineType: HP HP Spectre Notebook
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.13.0-12-generic root=UUID=4989886a-f95e-4802-ab51-dcbf53167aeb ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.13.0-12-generic N/A
 linux-backports-modules-4.13.0-12-generic N/A
 linux-firmware 1.169
SourcePackage: linux
UpgradeStatus: Upgraded to artful on 2017-08-31 (37 days ago)
dmi.bios.date: 02/21/2017
dmi.bios.vendor: Insyde
dmi.bios.version: F.31
dmi.board.asset.tag: Type2 - Board Asset Tag
dmi.board.name: 81A0
dmi.board.vendor: HP
dmi.board.version: 48.54
dmi.chassis.type: 10
dmi.chassis.vendor: HP
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnInsyde:bvrF.31:bd02/21/2017:svnHP:pnHPSpectreNotebook:pvrType1ProductConfigId:rvnHP:rn81A0:rvr48.54:cvnHP:ct10:cvrChassisVersion:
dmi.product.family: 103C_5335KV G=N L=CON B=HP S=SPT
dmi.product.name: HP Spectre Notebook
dmi.product.version: Type1ProductConfigId
dmi.sys.vendor: HP

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.14 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.14-rc4

[Max Bowsher (maxb)]

Unfortunately as the issue is intermittent, it is difficult to pinpoint a starting version exactly, but here's my best attempt:

Ubuntu zesty 4.10 series: definitely not affected

Ubuntu artful 4.12 kernels: problem not observed, though other iwlwifi issues (bug 1719210) observed - probably not affected

Ubuntu artful 4.13 kernels: 4.13.0-12.13 (current) definitely affected, unable to conclusively comment if earlier artful versions affected or not, due to already swapping kernels around a lot at the time troubleshooting the other mentioned bug.

It's worth noting that there is a large change in the versions of the Intel iwlwifi firmware microcode loaded to the device between these mentioned kernel versions. Regrettably newer versions of the kernel have dropped support entirely for interacting with the known good microcode version, so it isn't possible to test changing the kernel and microcode versions independently.

[Max Bowsher (maxb)]

It is not possible to test the latest upstream kernel. It appears to introduce further problems apparently related to apparmor which prevent dhclient running, preventing a wifi connection from being successful at all, as well as apparently causing display flickering, which is barely perceptible at first glance, but stressful to observe whilst attempting any substantial computer use.

[Kai-Heng Feng (kaihengfeng)]

Please use kernel parameter "apparmor=0" to temporarily disable apparmor.

[James Thomas Durkin (jdurkin85)]

I am seeing a similar issue on the Broadcom WL driver in 17.10 with the latest 4.13 kernel. websites start responding extremely slow as if there is intermitted total packet loss. Maybe this isn't limited to iwlwifi?

[Bryan Petty (tierra)]

I upgraded my Dell 5520 laptop from Zesty to Artful over a month ago now, and I'm seeing behavior pretty much exactly as described by Max, starting immediately after the upgrade. I've been stuck either plugging into my wired ethernet adapter, tethering with my phone, or just living without connectivity because the wifi connection has been so unreliable. Sometimes (frequently right after a clean boot) it works just fine, and I'm having no problems meeting sustained, reliable, fast speeds for maybe a minute, but it breaks down pretty quickly (sometimes even just after just 10 to 15 seconds after wifi connects), and I see nothing but long windows of 100% packet loss. If I monitor long enough, it seems to recover for a brief window of time, but pretty quickly goes right back to 100% packet loss (in windows of maybe 30 seconds to a few minutes).

This has been observed even today with the latest 4.13.0-19-generic kernel.

For the first week or two after the upgrade, I've been trying to determine if it was just limited to specific access points I was using, but I've observed this same behavior while connected to 3 different locations, with 3 wildly different wifi systems.

I also thought it might be the wifi adapter drivers in a kernel upgrade (this laptop has a builtin Intel Wireless 8265 card, using iwlwifi), so I picked up an Archer T4UH V2 (based on the Realtek RTL8812AU chipset) just in case using a different wifi driver would be enough to have working wifi again, but I'm seeing the same behavior with that adapter as well.

So it certainly seems related to wifi functionality only, but also not driver specific.

[Bryan Petty (tierra)]

Following up on my last report here, it seems like my issues have been resolved in the last week or two here. I didn't keep track close enough to figure out if it was a recent package/kernel update or not, but just wanted to note that I'm no longer seeing this intermittent packet loss anymore over wifi.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]