How do I fix "failed to map segment from shared object" error in Python?

I'm making a Python program that limits the available memory when running the program.
When tested with a limit of 1, 2, 3, 4 and 5 MB of memory, the following error occurs if the memory is limited to 3 or 4 MB.

./Main: error while loading shared libraries: libc.so.6: failed to map segment from shared object
Command '['./Main']' returned non-zero exit status 127.

The libc.so.6 file is in this location.

/usr/lib64/libc.so.6

This is my code.

import resource
import subprocess
import os

MEMORY_LIMIT = 3 * 1024 * 1024
resource.setrlimit(resource.RLIMIT_AS, (MEMORY_LIMIT, MEMORY_LIMIT))
soft, hard = resource.getrlimit(resource.RLIMIT_AS)
rlimit = ("pid {pid} soft {soft} hard {hard}"
        .format(pid=os.getpid(), soft=soft, hard=hard))
print(rlimit)
try:
    r=subprocess.run(['./Main'], check=True)
except Exception as e:
    print(e)

And it's Main.c code.

#include <stdio.h>
int main() {
    int a, b;
    scanf("%d %d", &a, &b);
    printf("%d\n", a+b);
    return 0;
}

I compiled it using the "gcc -o Main -O2 -Wall Main.c" command.

My question is:

1. It runs normally when the memory limit is 5MB, but why does this error occur when the limit is 3 or 4MB is limited?
2. Unlike RLIMIT_AS, why does RLIMIT_DATA or RLIMIT_STACK work well regardless of memory limitations?

Please answer me what the problem is.