Unfortunately this can only be seen in the kernel logs (though in kernel 4.13+ it’s also in /proc/vmstat, the oom_kill counter

http_2xx_auth:
      prober: http
      timeout: 5s
      http:
        valid_http_versions: ["HTTP/1.1", "HTTP/2"]
        method: GET
        no_follow_redirects: false
        preferred_ip_protocol: "ip4"
        fail_if_ssl: false
        fail_if_not_ssl: false
        tls_config:
          insecure_skip_verify: false
          ca_file: "{{ blackbox_exporter_config_path }}/{{ blackbox_exporter_config_ca_name }}"
        basic_auth:
          username: "{{ global_basic_auth_login }}"
          password: "{{ global_basic_auth_password }}"