Created attachment 305047 [details]
journalctl_651.log

I've observed a slow boot and shutdown/reboot problems that have been verified on the stock Arch 6.5.1, CachyOS 6.5.0-2 and a custom-compiled 6.5.1 Kernel. I originally had seen a RCU-related trace which I thought to be the cause for these problems as well and reported it in https://bugzilla.kernel.org/show_bug.cgi?id=217864. However that specific trace turned out to be caused by an old patch that I carried around with me since 2022.

systemd-analyze with my custom compiled 6.5.1 shows a suspiciously long firmware time:
Startup finished in 2min 42.000s (firmware) + 4.201s (loader) + 6.895s (kernel) + 1.541s (userspace) = 2min 54.640s  
graphical.target reached after 1.539s in userspace.

For comparison, 6.4.14 starts in 16 seconds and doesn't even show a firmware section.

System:
  Host: klx99 Kernel: 6.5.1-3.1-cachyos-lto arch: x86_64 bits: 64
    Desktop: KDE Plasma v: 5.27.7 Distro: CachyOS
Machine:
  Mobo: Lenovo model: X99-TF Gaming v: G368J V1.1, NALEX
    serial: <superuser required> UEFI: American Megatrends v: CX99DE26
    date: 10/10/2020
CPU:
  Info: 18-core model: Intel Xeon E5-2696 v3 bits: 64 type: MT MCP cache:
    L2: 4.5 MiB
Graphics:
  Device-1: AMD Navi 21 [Radeon RX 6950 XT] driver: amdgpu v: kernel
  Display: x11 server: X.Org v: 21.1.99 with: Xwayland v: 23.2.0 driver: X:
    loaded: amdgpu unloaded: modesetting dri: radeonsi gpu: amdgpu
    resolution: 2560x1440~165Hz
  API: OpenGL v: 4.6 Mesa 23.3.0-devel (git-8a32614a18) renderer: AMD
    Radeon RX 6950 XT (navi21 LLVM 16.0.6 DRM 3.54 6.5.1-3.1-cachyos-lto)