webpack less -> css with source maps via extracttextplugin

webpack.config.js

var webpack = require("webpack");
var ExtractTextPlugin = require("extract-text-webpack-plugin");

var lessLoader = ExtractTextPlugin.extract(
  "css?sourceMap!less?sourceMap"
);

module.exports = {
  cache: true,
  entry: { bundle: "./master/client/index.jsx" },
  output: {
    path: __dirname + "/master/public/js",
    filename: "[name].js"
  },
  devtool: "source-map",
  resolve: {
    extensions: ["", ".webpack.js", ".web.js", ".js", ".jsx"]
  },
  module: {
    loaders: [
      { test: /\.less$/, exclude: /node_modules/, loader: lessLoader },
      { test: /\.(eot|svg|ttf|woff|woff2)$/, exclude: /node_modules/, loader: "file" },
      { test: /\.jsx?$/, exclude: /node_modules/, loader: "babel?stage=1" }
    ]
  },
  plugins: [
    new ExtractTextPlugin("styles.css", {allChunks: true})
  ]
};