Comment 6 for bug 1929926

Hi again,
I know it is prio-low for everyone, but still thanks for your patience!
Plenty of other things now finally are out of the way, so I tried to test the current broken'ness of this before starting a SRU.

1. Create a s390x KVM guest, for example via, but not limited to:
$ uvt-kvm create --password=ubuntu testguest release=focal arch=s390x label=daily
# Note: do so with the various qemu versions that are to be tested.

In my example I had
Focal: 1:4.2-3ubuntu6.17
Hirsute: 1:5.2+dfsg-9ubuntu3.1

2. In that guest prep the load so kindly outlined in comment #3 (slightly adapted to match)
Note you have to run those as root
# prereq
$ apt install binutils
# define probe
$ echo "r:bash_readline /usr/bin/bash:0x$(nm -D /usr/bin/bash | awk '/T readline$/ {print $1}')" > /sys/kernel/debug/tracing/uprobe_events

# check if the probe is active and enable it
$ cat /sys/kernel/debug/tracing/uprobe_events
r:uprobes/bash_readline /usr/bin/bash:0x00000000000dd250
$ echo 1 >/sys/kernel/debug/tracing/events/uprobes/bash_readline/enable

# Start bash to trigger some traces
$ /usr/bin/bash -c 'echo $BASH_VERSION'
5.0.17(1)-release

# Check if traces happened
$ cat /sys/kernel/debug/tracing/trace
root@testguest2:~# cat /sys/kernel/debug/tracing/trace
# tracer: nop
#
# entries-in-buffer/entries-written: 2/2 #P:1
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
            bash-1653 [000] d... 540.252440: bash_readline: (0x2aa377b590e <- 0x2aa3785d250)
            bash-1653 [000] d... 555.642396: bash_readline: (0x2aa377b590e <- 0x2aa3785d250)

So far this just works, I see the uretprobes happening in the trace.
But neither my test bash nor the one that I'm in logged into the guest crashed/stopped in any way.
This is true for both tested qemu versions.

Is this only affecting emulated s390x?
Is there something else I miss to recreate this?