Nginx php-fpm No input file specified

When accessing PHP files from location block that have different document root specified using alias, i get error

No input file specified.

Here is the Nginx config i used

server {
    listen 80;
    server_name lab.test;
    root /www/lab.test/html;
    autoindex on;
    index index.php;

    location /ok/ {
        alias /www/serverok.test/html/;

        location ~ \.php$ {
            include snippets/fastcgi-php.conf;
            fastcgi_intercept_errors on;
            fastcgi_buffers 16 16k;
            fastcgi_buffer_size 32k;
            fastcgi_pass unix:/run/php/php7.4-fpm-boby.sock;
        }

    }

    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_intercept_errors on;
        fastcgi_buffers 16 16k;
        fastcgi_buffer_size 32k;
        fastcgi_pass unix:/run/php/php7.4-fpm-boby.sock;
    }
}

If I access an HTML file or any non-PHP file, it works properly from/ok/ location.

The problem is due to php-fpm not able to find the proper path when using the alias. If I put the PHP files inside a folder /ok/, it worked.

To fix the problem, add the following code before fastcgi_pass

fastcgi_param    SCRIPT_FILENAME    $request_filename;
fastcgi_param    SCRIPT_NAME        $fastcgi_script_name;

Example