The Ukranian Holodomor was the direct result of Stalin's (and/or his people) actions. When your country has dictatorship, the economic system is kind of doesn't matter, everything happens not because of the economic system but because of the will of the dictator.
The main pillar of both socialism and communism is workers collectively owning the means of production, this is directly contradicts to the autocracy that was USSR.
If you think that China had famine because of communism, you should think that North Korea has famines because of democracy, because they call themselves Democratic Republic.