Function_graph cannot track a specific function - linux

Question

When I use Function_graph to trace the do_sys_open () function, I find it doesn't work.
Linux version 4.4.194
echo function_graph > current_tracer
echo do_sys_open > set_graph_function
echo 1 > tracing_on
cat trace
root#firefly:/sys/kernel/debug/tracing# cat set_ftrace_filter | grep do_sys_open
do_sys_open
root#firefly:/sys/kernel/debug/tracing# cat trace
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
1) 0.583 us | } /* cpu_needs_another_gp */
1) 0.583 us | rcu_all_qs();
1) + 29.750 us | } /* rcu_check_callbacks */
1) | scheduler_tick() {
1) | _raw_spin_lock() {
1) 0.583 us | do_raw_spin_lock();
1) 5.833 us | }
1) 0.875 us | update_rq_clock();
1) | task_tick_fair() {
1) | update_curr() {
1) 0.583 us | update_min_vruntime();
1) 0.875 us | cpuacct_charge();
1) + 11.375 us | }
1) 0.583 us | cpufreq_scale_freq_capacity();
1) | scale_cpu_capacity() {
1) 0.583 us | cpufreq_scale_max_freq_capacity();
1) 5.541 us | }
1) 0.583 us | __compute_runnable_contrib();
1) 0.583 us | cpufreq_scale_freq_capacity();
1) | scale_cpu_capacity() {
1) 0.291 us | cpufreq_scale_max_freq_capacity();
1) 5.542 us | }
1) 0.583 us | update_cfs_shares();
1) 0.583 us | hrtimer_active();
1) | sched_slice.isra.8() {
1) 0.584 us | __calc_delta();
1) 5.833 us | }
1) 0.583 us | __cpu_overutilized.constprop.22();
It seems that it outputs all the tracking functions.
Function_graph and function tracker are found to be ineffective on the ARM64 development board of Linux version 4.4.194.
After echo do_sys_open > set_graph_function, all functions will still be tracked.
But it is effective in Linux version 5.4.0-135 Ubuntu 18.04. I wonder if it's the kernel version.