It's like 2 Bettas trying to get into each other's bowls.I doubt Russia would be much interested in going to bat (heh) for China in a shooting war outside of selling them weapons because, ultimately, they're still another geopolitical rival who has been eyeing all those natty resources in Siberia with interest.
Even Stalin and Mao could not get along. Marxism had to be sinoized for them to accept it.
China has a gigiantic economy, Russia is about on par with Italy. While they have a lot of resources, it's not like China's buying them. The only reason they would go hot on Russia is to lock the market up for rare Earth metals and fissile materials. China could beat them in the economic game more easily.