strace包含子线程，但是不想包含创建的子进程。怎么办呢？
使用-f选项，是会跟踪子进程的。需要使用-b选项
Tracing
-b syscall
--detach-on=syscall
If specified syscall is reached, detach from traced process. Currently, only ex‐
ecve(2) syscall is supported. This option is useful if you want to trace multi-
threaded process and therefore require -f, but don't want to trace its (potentially
very complex) children.