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FS#66447 - [linux] wifi stops and kworker stuck at 100 %cpu

Attached to Project: Arch Linux
Opened by Max Gautier (VannTen) - Tuesday, 28 April 2020, 13:31 GMT
Last edited by freswa (frederik) - Tuesday, 28 April 2020, 13:50 GMT
Task Type Bug Report
Category Kernel
Status Assigned
Assigned To Tobias Powalowski (tpowa)
Jan Alexander Steffens (heftig)
Levente Polyak (anthraxx)
Architecture x86_64
Severity Medium
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 0%
Votes 1
Private No



Seemingly at random, networks stops working and kworker takes 100% cpu.

I encountered 2 times in the last 10 days or so (which makes me think it is not just a glitch) the following situation.

Network stops working. By that, I mean requests never ends. Both times I was browsing in firefox and pages never finish to load.
At the same time, I get a 100% cpu usage in top of a kworker named "kwoker/u8:10+phy0" (I'm not sure about the 10, but the other
parts were the same both times).
The rest of the system stays responsive.

I try to restart my network manager service with systemctl (I use nectl, specifically netctl-auto), nut the command hangs and do nothing.
The service appears to be up and running, and there is nothing related to a failure in the logs (of the service).

I use hibernate a lot, might be relevant.

I'm note sure where that comes from, but the kworker and the lacks of any info in userspace logs makes me thinks it's somehow kernel related.
Should I report this upstream or can it be specific to the arch kernel ?

Additional info:
* package versions
- linux 5.6.6.arch1-1
- netctl 1.21

* lscpi info for ethernet (is that one relevant ?) and network controller
00:19.0 Ethernet controller: Intel Corporation Ethernet Connection (3) I218-LM (rev 03)
DeviceName: Onboard LAN
Subsystem: Dell Ethernet Connection (3) I218-LM
Flags: bus master, fast devsel, latency 0, IRQ 49
Memory at f7300000 (32-bit, non-prefetchable) [size=128K]
Memory at f7343000 (32-bit, non-prefetchable) [size=4K]
I/O ports at f080 [size=32]
Capabilities: [c8] Power Management version 2
Capabilities: [d0] MSI: Enable+ Count=1/1 Maskable- 64bit+
Capabilities: [e0] PCI Advanced Features
Kernel driver in use: e1000e
Kernel modules: e1000e
02:00.0 Network controller: Intel Corporation Wireless 7265 (rev 59)
Subsystem: Intel Corporation Dual Band Wireless-AC 7265
Flags: bus master, fast devsel, latency 0, IRQ 50
Memory at f7100000 (64-bit, non-prefetchable) [size=8K]
Capabilities: [c8] Power Management version 3
Capabilities: [d0] MSI: Enable+ Count=1/1 Maskable- 64bit+
Capabilities: [40] Express Endpoint, MSI 00
Capabilities: [100] Advanced Error Reporting
Capabilities: [140] Device Serial Number 10-02-b5-ff-ff-9a-ea-61
Capabilities: [14c] Latency Tolerance Reporting
Capabilities: [154] L1 PM Substates
Kernel driver in use: iwlwifi
Kernel modules: iwlwifi

* config and/or log files etc.
I'm attaching the output of `journalctl -k --boot=-1` which does seem to contains iwlwifi related messages ; I can't say if there are relevant though.

Steps to reproduce:
Unable to reproduce, unfortunately...

Please don't hesitate if I can provide more information on my system or the bug somehow.
   kernel.log (101.6 KiB)
This task depends upon

Comment by Max Gautier (VannTen) - Thursday, 30 April 2020, 10:00 GMT
I got the same problem today.
Here is the kernel log, looks similar.
I'm beginning to wonder if it's more of a hardware problem...
Comment by Martin Zecher (MartinZ) - Tuesday, 19 May 2020, 01:11 GMT
I'm experiencing this sometimes twice a day, I don't really think that it's a hardware problem.
I'm currently running linux-ck-ivybridge 5.6.13-1
Comment by Max Gautier (VannTen) - Wednesday, 24 June 2020, 16:09 GMT

Upstream report. ==> it has a patch which I tested and fixed the problem for me.