@navi Did you put the appropriate GIT_PROJECT_ROOT and have GIT_HTTP_EXPORT_ALL="" for your fcgi variables?
Like in my nginx config I have this:
# git-http-backend isnt fastcgi so fcgiwrap is needed fastcgi_param PATH_INFO $fastcgi_path_info; fastcgi_pass unix:/var/run/fcgiwrap/sock; fastcgi_split_path_info ^(/git)(.*); include fastcgi_params; fastcgi_param SCRIPT_FILENAME /usr/libexec/git-core/git-http-backend; fastcgi_param GIT_PROJECT_ROOT /git; fastcgi_param GIT_HTTP_EXPORT_ALL "";