Description:
When a "linux" kernel package upgrade is performed via pacman, the "/lib/modules/5.15.8-arch1-1" directory for the running kernel is deleted, and another modules subdirectory is created for the new upgraded kernel version.
This is problematic because we are left with an unstable system until reboot. Modules that are already loaded into memory works fine, but if an attempt is made to load a previously unloaded module, it will fail because the files containing the desired module no longer exist. This is not always obvious to the user, error messages may vary from application to application.

If we plug in a new device (USB pendrive, webcam, gamepad) while in this upgraded-but-not-yet-rebooted state, it will most certainly fail.

I think the running kernel's module directory should remain there while that kernel is still running and should be scheduled for deletion only after a reboot.

Additional info:
I'm currently on linux 5.15.8.arch1-1

Steps to reproduce:
1 - Wait for an upgrade to "linux" package to be available.
2 - Upgrade your kernel, pacman -Syu
3 - Take note of your running kernel version, uname -r
4 - $ ls /lib/modules
5 - Realize there is no subdirectory for the running kernel. There is only the upgraded kernel subdirectory, which will only run after a reboot
6 - Plug in a USB pendrive
7 - Realize you can't mount it (unless you had successfully mounted it before the upgrade on the same boot)