能访问index.html但不能访问index.php是怎么回事？

user www www;
worker_processes auto;

error_log /data/wwwlogs/error_nginx.log crit;
pid /var/run/nginx.pid;
worker_rlimit_nofile 51200;

events {
  use epoll;
  worker_connections 51200;
  multi_accept on;
}

http {
  include mime.types;
  default_type application/octet-stream;
  server_names_hash_bucket_size 128;
  client_header_buffer_size 32k;
  large_client_header_buffers 4 32k;
  client_max_body_size 1024m;
  client_body_buffer_size 10m;
  sendfile on;
  tcp_nopush on;
  keepalive_timeout 120;
  server_tokens off;
  tcp_nodelay on;

  fastcgi_connect_timeout 300;
  fastcgi_send_timeout 300;
  fastcgi_read_timeout 300;
  fastcgi_buffer_size 64k;
  fastcgi_buffers 4 64k;
  fastcgi_busy_buffers_size 128k;
  fastcgi_temp_file_write_size 128k;
  fastcgi_intercept_errors on;

  #Gzip Compression
  gzip on;
  gzip_buffers 16 8k;
  gzip_comp_level 6;
  gzip_http_version 1.1;
  gzip_min_length 256;
  gzip_proxied any;
  gzip_vary on;
  gzip_types
    text/xml application/xml application/atom+xml application/rss+xml application/xhtml+xml image/svg+xml
    text/javascript application/javascript application/x-javascript
    text/x-json application/json application/x-web-app-manifest+json
    text/css text/plain text/x-component
    font/opentype application/x-font-ttf application/vnd.ms-fontobject
    image/x-icon;
  gzip_disable "MSIE [1-6]\.(?!.*SV1)";

  #If you have a lot of static files to serve through Nginx then caching of the files' metadata (not the actual files' contents) can save some latency.
  open_file_cache max=1000 inactive=20s;
  open_file_cache_valid 30s;
  open_file_cache_min_uses 2;
  open_file_cache_errors on;

######################## default ############################
  server {
    listen 80;
    server_name _;
    access_log /data/wwwlogs/access_nginx.log combined;
    root /data/wwwroot/default;
    index index.html index.htm index.php;
    #error_page 404 /404.html;
    #error_page 502 /502.html;
    location /nginx_status {
      stub_status on;
      access_log off;
      allow 127.0.0.1;
      deny all;
    }
    location ~ [^/]\.php(/|$) {
      #fastcgi_pass remote_php_ip:9000;
      fastcgi_pass unix:/dev/shm/php-cgi.sock;
      fastcgi_index index.php;
      include fastcgi.conf;
    }
    location ~ .*\.(gif|jpg|jpeg|png|bmp|swf|flv|mp4|ico)$ {
      expires 30d;
      access_log off;
    }
    location ~ .*\.(js|css)?$ {
      expires 7d;
      access_log off;
    }
    location ~ /\.ht {
      deny all;
    }
  }
########################## vhost #############################
  include vhost/*.conf;
########################## WAF #############################
    lua_shared_dict limit 10m;
    lua_package_path "/usr/local/openresty/nginx/conf/waf/?.lua";
    init_by_lua_file "/usr/local/openresty/nginx/conf/waf/init.lua";
    access_by_lua_file "/usr/local/openresty/nginx/conf/waf/waf.lua";
}