It is not vfork, it is similar to rfork in FreeBSD but note that fork(), vfork(), and __clone() all invoke clone() in Linux post 2.4. The costs of copying the parent tables and creating the task is the only additional cost for fork(), which is very different than the didactic explanation of fork()+exec().

https://man7.org/linux/man-pages/man2/fork.2.html

"C library/kernel differences Since version 2.3.3, rather than invoking the kernel's fork() system call, the glibc fork() wrapper that is provided as part of the NPTL threading implementation invokes clone(2) with flags that provide the same effect as the traditional system call. (A call to fork() is equivalent to a call to clone(2) specifying flags as just SIGCHLD.) The glibc wrapper invokes any fork handlers that have been established using pthread_atfork(3)."