Is there a safe way to make UCX work in the child process?

[Swiftie13st]

Hello, I’m currently using UCX 1.81.1. My application loads data via a child process via fork() midway through, at which point ucx has already been called multiple times, then the program hangs after forking even with env UCX_IB_FORK_INIT=y enabled. Reinitializing UCX didn’t resolve the issue #4325
After modifying the example code, the problem can be reproduced, the UCX in the child process does not work properly.
Is there a safe way to make UCX work in the child process? (using RDMA IB)

Here is the code modified based on /examples/ucp_client_server.c +1130 :

/* Client-Server initialization */
if (server_addr == NULL) {
    /* Server side */
    ret = run_server(ucp_context, ucp_worker, listen_addr, send_recv_type);
} else {
    /* Client side */
    ret = run_client(ucp_context, server_addr, send_recv_type);

    pid = fork();
    if (pid == 0) {
        // not reinit -> Caught signal 11 (Segmentation fault: address not mapped to object at address 0x55e892795000)
        ret = init_context(&ucp_context1, &ucp_worker1, send_recv_type);
      if (ret != 0) {
            goto err;
        }
        printf("%p, %p", (void *)ucp_context,  (void *)ucp_context1);

        // but this will hang
        ret = run_client(ucp_worker1, server_addr, send_recv_type);
    } else {
        waitpid(pid, NULL, 0);
    }
}