$ sudo ./vfork_newpid vfork_newpid: PID: 8479 vfork_newpid: PID 8479 exiting after execve(2): Successprint_pid: PID 1 exiting.
I definitely think this is a kernel (or glibc) bug. execve(2) is supposed to _never_ return 0 (and errno 0). I submitted a new bug to discuss it. Please see <https://bugzilla.kernel.org/show_bug.cgi?id=215813>