second call prctl() dont work - linux

Question

I try write program, which realize next idea:
After start, program using fork() and:
parent process stopped on function wait() (for waiting death child process);
child process use prctl(PR_SET_PDEATHSIG, SIGHUP), and setup signal handler (It's helps detect parent death);
After death any process, program use fork() again.
void forking_process() {
pid_t id;
printf("forking_process is called!\n");
if (id = fork()) {
parent_process_operation();
} else {
child_process_operation();
}
}
void parent_process_operation() {
int status = 0;
printf("It's parent process! Pid = %d\n", (int)getpid());
pid_t chid = wait(&status);
printf("Terminated child process with PID = %d\n", chid);
inform_about_parent_death(status);
}
void child_process_operation() {
printf("It's child process! pid = %d, ppid = %d\n",
(int)getpid(), (int)getppid());
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = inform_about_parent_death;
if (sigaction(SIGHUP, &sa, NULL))
fprintf(stderr, "sigaction error\n");
prctl(PR_SET_PDEATHSIG, SIGHUP);
while(1) {
printf("."); fflush(stdout);
sleep(1);
}
}
void inform_about_parent_death(int i) {
printf("Process is dead. Restart!\n");
forking_process();
}
int main (void) {
forking_process();
return EXIT_SUCCESS;
}
If I run this application, and in another terminal kill child process - then will create child process.
If I kill the parent process once, - signal handler started and call fork().
If I again kill the parent process, - signal handler not responded.
That is - prctl() in first process work, but prctl() in second child process don't work.
Why it is happen? How I can correct it's program?