I am using code-server-3.3.0-linux-amd64.tar.gz and the search is broken - the following file is missing the +x (execute) flag
code-server-3.3.0-linux-amd64/lib/vscode/node_modules/vscode-ripgrep/bin/rg.
Simple workaround is to run in the root of code-server folder: chmod +x lib/vscode/node_modules/vscode-ripgrep/bin
sudo chmod +x /usr/lib/code-server/lib/vscode/node_modules/vscode-ripgrep/bin/rg
Most helpful comment
sudo chmod +x /usr/lib/code-server/lib/vscode/node_modules/vscode-ripgrep/bin/rg