Arch Linux

Kepis

Member

Registered: 2021-12-15

Posts: 105

[Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

I am using a laptop (IdeaPad 5 Pro - AMD 7 5800H, WiFi mt7921e), it works (most of the time).
Whenever I restart the device, I get to GUI, but after a couple of seconds, the CapsLock LED starts flashing and the system freezes.
This behaviour is linux specific, I haven't experienced this when testing with Windows.

Last edited by Kepis (2022-04-15 10:34:36)

paulkerry

Member

From: Sheffield, UK

Registered: 2014-10-02

Posts: 611

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

Sounds like a kernel crash with flashing leds. You didn't post any logs or indicate which kernel you are using.
Try installing and using another kernel, like the lts kernel - https://wiki.archlinux.org/title/Kernel … ed_kernels

siegestarscream

Member

Registered: 2022-02-17

Posts: 2

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

If you mean normal shutting down and starting are fine, then it may be a Lenovo/AMD hardware problem. My Legion 5 Pro faces the same issue.

Kepis

Member

Registered: 2021-12-15

Posts: 105

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

Sounds like a kernel crash with flashing leds. You didn't post any logs or indicate which kernel you are using.
Try installing and using another kernel, like the lts kernel - https://wiki.archlinux.org/title/Kernel … ed_kernels

Yes indeed, the lts kernel fixed this, but I still wonder, what could be the reason for such an issue.

JoeyCorleone

Member

Registered: 2022-01-22

Posts: 88

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

If the issue is present in the current linux package (v5.16) but not in the linux-lts package (currently tracking v5.15), it means this is probably a bug in the kernel.
It will work for you until the linux-lts package starts tracking a newer kernel version. So, your solution is by no means permanent.

In an ideal world, you would bisect the 5.16 kernel to find the offending commit and report it. Unfortunately, that is not an easy task.

Your other best solution is to hope someone else digs around and fixes or reports this issue.

Kepis

Member

Registered: 2021-12-15

Posts: 105

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

you're right, the 1.16.0 kernel has this issue already present, but 1.15.8 does not.

paulkerry

Member

From: Sheffield, UK

Registered: 2014-10-02

Posts: 611

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

1.16.0 kernel has this issue already present, but 1.15.8 does not.

Maybe you mean 5.16.0 and 5.15.8 (the title of your post has 1.16.0 too)
Also make sure you are using the most up to date kernels: currently these are 5.16.10.arch1-1 and 5.15.24-1 (lts)

Last edited by paulkerry (2022-02-21 11:05:36)

Kepis

Member

Registered: 2021-12-15

Posts: 105

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

Yes, but this way I verified the bug was introduced with kernel 5.16.0

paulkerry

Member

From: Sheffield, UK

Registered: 2014-10-02

Posts: 611

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

OK: what I'm getting at is if you only tried 5.16.0, there is a chance the issue you experienced has already been fixed in the releases from 5.16.1->5.16.10

Kepis

Member

Registered: 2021-12-15

Posts: 105

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

Yes, I know, but it isn't.

loqs

Member

Registered: 2014-03-06

Posts: 18,859

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

Have you tested 5.17-rc5?

https://bbs.archlinux.org/viewtopic.php … 9#p2016749 contains the first bisection point from 5.15 to 5.16 you could test that and while your results match that of the bisection the kernels from the posts after it.  That issues was fixed in 5.16.9.

Kepis

Member

Registered: 2021-12-15

Posts: 105

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

I keep up to date and made this post mainly because of the annoyance it is still present. I am not sure about what you are reffering to. But I shall give the 5.17-rc5 a try.

loqs

Member

Registered: 2014-03-06

Posts: 18,859

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

I was suggesting you could test the kernel from https://bbs.archlinux.org/viewtopic.php … 9#p2016749 if that did not work you would try the kernel from post #12 of that thread and as long as your results matched isaac_le you would keep testing the kernels until the results diverged.  Then you ( or I could for you) build the rest of the kernels to complete the bisection.

Kepis

Member

Registered: 2021-12-15

Posts: 105

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

Ok, thanks for the explanation. I will try my best.

Kepis

Member

Registered: 2021-12-15

Posts: 105

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

Also, I suppose you meant 5.15-rc5, as I can't see any post with 5.17

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,104

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

No, they meant 5.17-rc5 which is the current release candidate you could e.g. easily get via the AUR: https://aur.archlinux.org/packages/linux-mainline or alternatively if you don't want to compile via the repo by the same maintainer: https://wiki.archlinux.org/title/Unoffi … ries#miffe

Last edited by V1del (2022-02-22 11:31:04)

Kepis

Member

Registered: 2021-12-15

Posts: 105

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

Oh, ok, thanks.

JoeyCorleone

Member

Registered: 2022-01-22

Posts: 88

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

Feel free to ask for more info if you need help installing and booting the mentioned kernels.

scennea

Member

Registered: 2022-03-17

Posts: 1

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

I had the same problem and replacing the wifi module by an AX200 absolutely solved the problem.

Kepis

Member

Registered: 2021-12-15

Posts: 105

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

I had the same problem and replacing the wifi module by an AX200 absolutely solved the problem.

Yeah, mediatek wifi sucks. It does much more things badly, than just affecting things it shouldn't.

Kepis

Member

Registered: 2021-12-15

Posts: 105

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

Unfortunately I just finally tried the 5.17.1 and found out the issue still persists.
When I reboot the laptop, the system-udevd processes do its thing and I think the moment they are finished it panics.

loqs

Member

Registered: 2014-03-06

Posts: 18,859

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

Are you able to try the kernels from the 5.15 to 5.16 bisection?  Without knowing which commit triggered the issue or the kernel messages from the panic this is no way to find the cause.
Edit:

I had the same problem and replacing the wifi module by an AX200 absolutely solved the problem.

Yeah, mediatek wifi sucks. It does much more things badly, than just affecting things it shouldn't.

Is there a mediatek WiFi adapter in the system?  If so which one?  Did you try with it removed / disabled?

Last edited by loqs (2022-03-30 01:07:56)

Maniaxx

Member

Registered: 2014-05-14

Posts: 761

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

I would start with
- memtest
- bios update
- disabling hardware in bios
- latest microcodes (cpu updates)

If this doesn't help try Kdump. Set it to at least 256MB and get a backlog with gdb.

---

sys2064

siegestarscream

Member

Registered: 2022-02-17

Posts: 2

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

Figured it out on Legion 5 Pro thanks to posts above, maybe similar on other Lenovo laptops. Try

lspci -k |grep mt

and see if there's a MediaTek wifi adapter driver in use. For me it's mt7921e,  so disable it by  writing something like

blacklist mt7921e

in /etc/modprobe.d/blacklist.conf . See if you can reboot successfully at the cost of your wireless connection. That seems to be the only solution for now.

Kepis

Member

Registered: 2021-12-15

Posts: 105

Re: [Solved] 5.16.0 Linux Kernel Panic after reboot - wifi mt7921e

I know it is caused by the stupid mediatek wifi card, but I need Internet.

Last edited by Kepis (2022-03-31 05:07:21)