Golang Fork/exec /bin/sh operation not permitted

package main

import (
    "fmt"
    "os"
    "os/exec"
    "syscall"
)

func main() {
    os.Setuid(1000)
    cmd := exec.Command("/bin/sh")

    cmd.Stdin = os.Stdin
    cmd.Stdout = os.Stdout
    cmd.Stderr = os.Stderr

    cmd.Env = []string{"PS1=-[ns-process]- # "}
    cmd.SysProcAttr = &syscall.SysProcAttr{
        Cloneflags: syscall.CLONE_NEWNS |
            syscall.CLONE_NEWUTS |
            syscall.CLONE_NEWIPC |
            syscall.CLONE_NEWPID |
            syscall.CLONE_NEWNET |
            syscall.CLONE_NEWUSER,
        UidMappings: []syscall.SysProcIDMap{
            {
                ContainerID: 0,
                HostID:      os.Getuid(),
                Size:        1,
            },
        },
        GidMappings: []syscall.SysProcIDMap{
            {
                ContainerID: 0,
                HostID:      os.Getgid(),
                Size:        1,
            },
        },
    }

    if err := cmd.Run(); err != nil {
        fmt.Printf("Error running the /bin/sh command - %s\n", err)
        os.Exit(1)
    }
}

Above is my code,but get the result is "Fork/exec /bin/sh operation not permitted" when running the program in root user.But it run correctly with uid 1000.

os: 5.15.55-1-MANJARO go version: 1.18.3