help! staprun no respose in pass 5

[lon chin]

I have a problem.
I build linux kernel 3.16.5,emerge systemtap.
run a test `stap -vv -e 'probe begin{printf("hello");exit()}'`

but no response after pass 5.
the tail stdout is :
Pass 5: starting run.
Running /usr/bin/staprun -v -R
/tmp/stapKlIFxX/stap_fe4fd472898f50668e6f2cea07dae8c9_859.ko
staprun:disable_kprobes_optimization:327 Disabled
/proc/sys/debug/kprobes-optimization.
staprun:insert_module:183 Module
stap_fe4fd472898f50668e6f2cea07dae8c_2117 inserted from file
/tmp/stapKlIFxX/stap_fe4fd472898f50668e6f2cea07dae8c9_859.ko

I do not kown how to find the error.