If I choose kernel 5.18.18 at the boot screen, everything works. I have saved journalctl -b and rdsosreport from the abortive 5.18.19 boot, so if someone can tell me what to look for, I will.
I do note that rdsosreport ends with
[ 8.167969] fedora systemd[1]: Reached target initrd-switch-root.target - Switch Root.
[ 8.169173] fedora systemd[1]: Starting initrd-switch-root.service - Switch Root...
[ 8.173647] fedora systemctl[813]: Failed to switch root: Specified switch root path '/sysroot' does not seem to be an OS tree. os-release file is missing.
[ 8.174257] fedora systemd[1]: initrd-switch-root.service: Main process exited, code=exited, status=1/FAILURE
[ 8.174363] fedora systemd[1]: initrd-switch-root.service: Failed with result 'exit-code'.
[ 8.190138] fedora systemd[1]: Failed to start initrd-switch-root.service - Switch Root.
[ 8.195075] fedora systemd[1]: Startup finished in 45.475s (firmware) + 4.163s (loader) + 4.133s (kernel) + 0 (initrd) + 4.062s (userspace) = 57.834s.
[ 8.195115] fedora systemd[1]: initrd-switch-root.service: Triggering OnFailure= dependencies.
[ 8.195176] fedora audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 subj=kernel msg='unit=initrd-switch-root comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=failed'
[ 8.195991] fedora systemd[1]: Started emergency.service - Emergency Shell.
But I don’t see why this should happen with 5.18.19 but not with 5.18.18.
What is sysroot? Where is it? How is os-release created? There’s one in /usr/lib, but it has info only on the F36 release; nothing specific to the kernel version.
Before this point, I had been trying to install Nvidia’s cuda-repo-fedora35-11-7-local-11.7.1_515.65.01-1.x86_64.rpm, which is only approved for F35, so that may well be the root of the problem, since I ended up having to remove the Nvidia drivers and move to nouveau.