Network connectivity lost after a few minutes on Intel Corporation Wireless 8265 / 8275 (rev 78), ThinkPad T480s, firmware v36

[Pirouette Cacahuète]

STR:
 - connect to Mozilla or Mozilla Guest wifi networks

After a few seconds / minutes (less than three in general), no more network connectivity, but no error reported in dmesg. Only solution is to disconnect / reconnect network.

To date, it does not happen at home, connected on a Netgear R7000 AP, the issue is somehow triggered by the infra at Mozilla (Paris office).
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ProblemType: Bug
ApportVersion: 2.20.10-0ubuntu13
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: alex 2871 F.... pulseaudio
CurrentDesktop: GNOME
DistroRelease: Ubuntu 18.10
HibernationDevice: RESUME=LABEL="Swap"
InstallationDate: Installed on 2012-11-03 (2196 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
MachineType: LENOVO 20L7CTO1WW
Package: linux (not installed)
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.18.0-10-generic root=UUID=45c5d738-161a-4a73-9614-c529fdf655be ro quiet splash vt.handoff=1
ProcVersionSignature: Ubuntu 4.18.0-10.11-generic 4.18.12
RelatedPackageVersions:
 linux-restricted-modules-4.18.0-10-generic N/A
 linux-backports-modules-4.18.0-10-generic N/A
 linux-firmware 1.175
Tags: cosmic
Uname: Linux 4.18.0-10-generic x86_64
UpgradeStatus: Upgraded to cosmic on 2018-10-22 (17 days ago)
UserGroups: adm cdrom dialout dip disk docker kismet libvirt libvirtd lpadmin plugdev sambashare sudo vboxusers video
_MarkForUpload: True
dmi.bios.date: 09/13/2018
dmi.bios.vendor: LENOVO
dmi.bios.version: N22ET49W (1.26 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20L7CTO1WW
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40697 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrN22ET49W(1.26):bd09/13/2018:svnLENOVO:pn20L7CTO1WW:pvrThinkPadT480s:rvnLENOVO:rn20L7CTO1WW:rvrSDK0J40697WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad T480s
dmi.product.name: 20L7CTO1WW
dmi.product.sku: LENOVO_MT_20L7_BU_Think_FM_ThinkPad T480s
dmi.product.version: ThinkPad T480s
dmi.sys.vendor: LENOVO

[Pirouette Cacahuète (lissyx)]

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[Pirouette Cacahuète (lissyx)]

After extensive playing with iwlwifi, I could stop the issue by doing either:
 - modprobe iwlwifi 11n_disable=1
 - blacklist the v36 firmware /lib/firmware/iwlwifi-8265-36.ucode, driver picks v34 which seems to be stable

I tested the two releases of v36: 36.7596afd4.0 and 36.e91976c0.0, both expose the same issue.

Given the impact on speed, I've chose the second solution as a workaround.

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

This change was made by a bot.

[Pirouette Cacahuète (lissyx)]

Aruba AP225 on ArubaOS v6.5.3.3

[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 v4.20 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/v4.20-rc2

[Pirouette Cacahuète (lissyx)]

It started right after my upgrade to 18.10 fron 18.04, and took me a few days to realize: at home the behavior was just that sometimes dns lookups were slower. I first blamed systemd-resolved until I got into the office and could debug more.

I got reports from colleagues om different distros / kernel and Wi-Fi chips, but all iwlwifi, and firmware v36.

I'm not sure I can find time soon to play with kernels from upstream. There was a 4.18-11 update recently, have not yet tried it. I'd need to check the changelog to see if there's any hope.

[Launchpad Janitor (janitor)]

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

[Pirouette Cacahuète (lissyx)]

None of the kernel upgrade for Cosmic would improve the situation. I've upgraded to Disco and keeping an eye on this.

[Pirouette Cacahuète (lissyx)]

Okay, after a few minutes under Disco, I'm still experiencing strange delays on WiFi on my home router, Netgear R7000, very very similar to the latencies on Mozilla's network. Revering to v34 firmware seems to workaround the issue.

> [ 6.367375] iwlwifi 0000:3d:00.0: loaded firmware version 36.9f0a2d68.0 op_mode iwlmvm
> [ 6.406151] iwlwifi 0000:3d:00.0: Detected Intel(R) Dual Band Wireless AC 8265, REV=0x230

[Pirouette Cacahuète (lissyx)]

Just came accross this: https://bugzilla.kernel.org/show_bug.cgi?id=199251

[Pirouette Cacahuète (lissyx)]

FTR, I cannot seem to reproduce anymore the issue on latest Disco release, at least on my home network. I'll keep posted wrt the Mozilla office network.

[Pirouette Cacahuète (lissyx)]

I could not reproduce in the Mozilla Paris office, both on the old network as well as the new one deployed after the move. So it looks like this got fixed.