Comment # 1 on bug 1146017 from Neil Rickert

I can confirm this.

My tests used a KVM virtual machine, where I installed Leap 15.2Alpha last
week.

I booted the DVD installer (the iso file used as a virtual DVD), selecting the
option to boot an installed linux system.  I described that failure in the
linked forum thread.

I tried again this morning, but with a difference.  I instead booted to the
rescue system.  My plan was to attempt to use kexec manually.

I mounted the root file system for the installed Leap 15.2 at "/mnt".  This was
a read-only mount to avoid problems of file system corruption.  I did not mount
any "btrfs" subvolumes, but the kernel and initrd files were visible on the
mounted system.

I recorded my attempt at "kexec" with the "script" command.  The recorded
"typescript" file went to volatile storage, since I was running from the DVD. 
After the "kexec" failed, I mounted the home partition for that installed
system (read-write mount) and copied the "typescript" file to there.

The output is short, so I'll just include here rather than attach:
 ---- begin typescript ----
Script started on 2019-08-18 13:29:35+00:00 [TERM="linux" TTY="/dev/tty1"
COLUMNS="128" LINES="48"]
rescue:/ # echo $x

rescue:/ # x=/mnt/boot/initrd-4*
rescue:/ # echo $x
/mnt/boot/initrd-4.12.14-lp152.28-default
rescue:/ # echo "$x"
/mnt/boot/initrd-4*
rescue:/ # x=`echo $x`
rescue:/ # echo "$x"
/mnt/boot/initrd-4.12.14-lp152.28-default
rescue:/ # y=/mnt/boot/vmlinuz-4*
rescue:/ # echo $y
/mnt/boot/vmlinuz-4.12.14-lp152.28-default
rescue:/ # kexec -l $y --append=root=/dev/sda5 --initrd=$x
rescue:/ # echo $?
0
rescue:/ # exit

Script done on 2019-08-18 13:32:08+00:00 [COMMAND_EXIT_CODE="0"]
 ---- end typescript ----

It looks as if "kexec" doesn't work (fails silently).