System hang after output "Reached target Basic System."

Hi
I'w working on a Greenlow platform Server. Now met an issue: System hang after output "Reached target Basic System."
My question is which function of kernel will output this message? I can continue to trace this issue if i can find the function name.

Thanks
[ 0.000000] tsc: Fast TSC calibration failed
ÿ[ 2.279076] i8042: No controller found
[ OK ] Started Show Plymouth Boot Screen.

[ OK ] Reached target Paths.

[ OK ] Reached target Basic System.