Unable to connect to sandbox-created Unix domain socket when waiting for connection using epoll_ctl about gvisor HOT 5 CLOSED

#define _GNU_SOURCE
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/epoll.h>


int main(int argc, char *argv[]) {
    int sock_fd = -1;
    int flags = 0;
    int ret = -1;
    int client_fd = -1;
    int epoll_fd = -1;
    struct epoll_event epoll_read = {
        .events = EPOLLIN|EPOLLPRI|EPOLLERR|EPOLLHUP|EPOLLET,
    };
    struct sockaddr_un addr = {0};
    char *sock_path = NULL;
    char *msg = NULL;

    if (argc < 3) {
        printf("<socket_path> <msg>\n");
        return 1;
    }

    sock_path = argv[1];
    msg = argv[2];

    epoll_fd = epoll_create1(EPOLL_CLOEXEC);
    if (epoll_fd < 0) {
        perror("epoll_create");
        return 1;
    }

    printf("socket\n");
    sock_fd = socket(AF_UNIX, SOCK_STREAM|SOCK_NONBLOCK, 0);
    if (sock_fd < 0) {
        perror("socket");
        return 1;
    }

    if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock_fd, &epoll_read) < 0) {
        perror("epoll_ctl");
        return 1;
    }

    printf("bind\n");
    unlink(sock_path);
    addr.sun_family = AF_UNIX;
    strcpy(addr.sun_path, sock_path);
    if (bind(sock_fd, &addr, sizeof(addr)) < 0) {
        perror("bind");
        return 1;
    }

    printf("listen\n");
    if (listen(sock_fd, 128) < 0) {
        perror("listen");
        return 1;
    }

    do {
        struct epoll_event ev[128] = {0};
        ret = epoll_wait(epoll_fd, ev, 128, -1);
    } while (ret < 0 && errno == EINTR);

    if (ret <= 0) {
        perror("epoll_wait");
        return 1;
    }

    printf("accept\n");
    client_fd = accept(sock_fd, NULL, NULL);
    if (client_fd < 0) {
        perror("accept");
        return 1;
    }

    printf("send: %s\n", msg);
    send(client_fd, msg, strlen(msg), 0);
    
    printf("done!\n");
    return 0;
}