error: failed to mmap. Could not write data: Permission denied

error: failed to mmap. Could not write data: Permission denied.

Getting this error while executing the following code

repository.fetchAll({
    callbacks: {
      certificateCheck: function () {
        return 0;
      },
      credentials: function (_url: string, userName: string) {
        return Git.Cred.sshKeyNew(
          userName,
          sshPublicKeyPath,
          sshPrivateKeyPath,
          ''
        );
      }
    }
  })

Start with the repository.fetchAll call and its credentials callback, then reproduce the mmap permission failure in the affected environment while checking the SSH key paths and filesystem permissions. Done means the cause is identified and documented or the fetch completes without the error, with a focused regression test if a relevant test entry point exists.