15:58 <arnd> I revisited my earlier problems running my own kernel that resulted in Xorg crashing with "free(): double free detected in tcache 2; (EE) Backtrace: ; (EE) 0: /usr/lib/xorg/Xorg (OsLookupColor+0x188) [0xaaaad77b8758] ; (EE) unw_get_proc_info failed: no unwind info found [-10]"

16:00 <arnd> finally narrowed it down to CONFIG_DRM_ASAHI=n

16:01 <arnd> my previously working kernel didn't contain the driver at all, and when I tried to reproduce building Glanzmann's working kernel build using the same sources and toolchain, it was still disabled because my rust toolchain was the wrong version

16:01 <arnd> Is there any way to get a working framebuffer these days without enabling DRM_ASAHI?

16:08 <mps> arnd: I could post you alpine kernel config, it worked previous week when I tested

16:09 <mps> https://git.alpinelinux.org/aports/tree/testing/linux-asahi/config-asahi.aarch64

16:11 <arnd> mps: Thanks! I might try that later, but I don't think the kernel config is actually the issue. I previously had a working kernel without DRM_ASAHI as well, but it broke after I installed the updated Debian libunwind.

16:12 <arnd> I managed to get it all working again after installing Glanzmann's custom libunwind and Xorg packages, but I guess something in those updates now requires the kernel driver

16:13 <mps> ah, iirc Glanzman told that default libunwind is broken on debian

16:14 <mps> did you upgrade mesa-dri-gallium from Glanzman repo

16:14 <mps> upgraded*

16:14 <arnd> yes, I added his repo and did a dist-upgrade with everything that was newer than the normal debian-stable

16:15 <mps> that is, mesa-asahi doesn't work without DRM_ASAHI, I had same problem

16:16 <mps> try downgrade mesa pkgs to debian default

16:17 <mps> arnd: though I'm not sure what Glanzman actually packaged in his repo, take my words with 'grain of salt' because I didn't tested his pkgs

16:18 <arnd> I can see that I have mesa packages versioned 23.0.0-202212211820 installed, which matches the files in https://thomas.glanzmann.de/asahi/pool/main/

16:19 <mps> looks like this could be your issue

16:20 <mps> try to downgrade mesa

16:20 <mps> last week I had to do this on my spare m1 where I do tests

16:25 <arnd> mps: it worked, thanks a lot!

16:25 <mps> arnd: np

17:04 <jannau> arnd: Xorg and/or mesa is not supposed to crash if the GPU driver is missing (DRM_ASAHI) and it doesn't here. (with a slightly older mesa asahi snapshot though, 20221219-1)

18:32 <arnd> jannau: Makes sense. I know nothing about Xorg internals, but my best guess would be that the 'double free' that gets reported in the log is the result of an actual bug in the error handling, while the following backtrace is meaningless because of yet another problem with the new libunwind

18:34 <arnd> I don't think it was introduced in a recent mesa snapshot, since I saw the same symptom a month ago