Arch Linux

There were no amdgpu changes in 5.8.7 [1]. Please test 5.8.8.arch1-1 currently in testing. If the issue is still present try 5.8.6.arch1-1.
Then bisect to find the causal commit and report the issue upstream if it has not already been reported upstream.

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.8.7.

For starters here are the package versions and their state.

* Good: linux-5.8.5.arch1-1
* Good: linux-5.8.6.arch1-1
* Bad: linux-5.8.7.arch1-1
* Bad: linux-5.8.8.arch1-1

Unfortunately could not get a trace of linux-5.8.8.arch1-1, seems like journald did not get the chance to write everything down and the kernel log is truncated.

You can try booting with slub_debug=FZP . Maybe it will catch some corruption.

removed (double-post due to browser refresh)

I tried bisecting from 5.8.6-arch1 to 5.8.7-arch1 starting from the repo package [1] as described in the wiki [2].
But, this being my first shot at bisecting anything, I blew it.

On the first attempt it built a 5.8.6 kernel exhibiting the bug -- promising so far.
Unfortunately upon running "git bisect bad" after testing it, I got:

f82a57f3fbc7dc23254d5ac2ab6f62227a8a288e was both good and bad

Here is the output of "git bisect log":

git bisect start
# good: [f82a57f3fbc7dc23254d5ac2ab6f62227a8a288e] Arch Linux kernel v5.8.6-arch1
git bisect good f82a57f3fbc7dc23254d5ac2ab6f62227a8a288e
# bad: [13c2d5cc731142ffd8f22aec0e644dcd99b78940] Arch Linux kernel v5.8.7-arch1
git bisect bad 13c2d5cc731142ffd8f22aec0e644dcd99b78940
# bad: [f82a57f3fbc7dc23254d5ac2ab6f62227a8a288e] Arch Linux kernel v5.8.6-arch1
git bisect bad f82a57f3fbc7dc23254d5ac2ab6f62227a8a288e

I must be missing out on something fundamental here. Shouldn't it have started at a commit smack in the middle between 5.8.6 and 5.8.7?
Also, how come I got a bad kernel, when it was built from the exact same commit of 5.8.6-arch1? I am running the good linux-5.8.6-arch1-1 from the Arch repos as I am typing this.

Edit: I did not use "make clean" in between builds; the first build I did was a 5.8.8-arch1 just to see if the PKGBUILD works.
This might at least explain the bad 5.8.6.

[1] https://www.archlinux.org/packages/core/x86_64/linux/
[2] https://wiki.archlinux.org/index.php/Bisecting_bugs_with_Git

Would have expected to see the following (assuming sphinx-workaround.patch was not applied or reset and docs were not built)
git bisect start
git bisect good v5.8.6-arch1
git bisect bad v5.8.7-arch1
Bisecting: a merge base must be tested
[66534fe2b9400003b0f49cc94686a162132b64e7] Linux 5.8.6

I applied Common Sense™ to the problem with some success, I think.

Since nobody else seems to have these errors, chances are they are caused by some particularity of my setup.
There were some HID core related fixes between 5.8.6 and 5.8.7, so I figured I should boot up with some of my USB stuff unplugged.

I have two USB devices that might not be all that common:

* Sony PS3 Dualshock 3 gamepad
* Apple Magic Trackpad 2

It seems if I boot up without the trackpad, then I don't get the kernel errors, neither with 5.8.7 nor with 5.8.8. Running linux-5.8.8-arch1-1 now.
Works for me, I don't use the trackpad much anyway, I just wanted to try it as an addition to the mouse.

Guess I'll take this one upstream [1].

[1] https://bugzilla.kernel.org/show_bug.cgi?id=209239