You can be more specific, without specificity all I can say is that most westerners' view of excess mortality in the Soviet Union comes from the Black Book of Communism, notoriously debunked "historical" book that included the following as "deaths due to Communism:"
- Nazis killed during World War II
- People the Nazis killed
- Non-births as deaths (such as increased access to contraceptives)
- Made-up numbers to get to the "100 million" figure everyone has heard of
- Came out before the release of the Soviet Archives
- Several of its own writers came out and denounced the book for being essentially mythology
No Marxist asserts that there were no excess deaths in Socialist states, that would certainly be off-base. However, us Marxists do affirm that historical record overwhelmingly favors the notion that the real historical totals are heavily distorted quantitatively and qualitatively in western media and education.
If you want to be specific, we can go further into detail, if you'd like.
Even the Wikipedia article opens up, affirming what I just said:
Even further, it attributes starvations in gulags occuring during World War II when the Nazis invaded Ukraine, the USSR's breadbasket, to the USSR rather than Nazi Germany. It also includes all executions as "excess deaths," presumably implying any execution is unjustified, even those of fascists and the members of the White Army that had committed crimes against humanity.
The article even says the 20 million number commonly reported is bogus, and the actual number of deliberate deaths is less than 5% of that, and among those deliberate deaths were legitimate executions of murderers, rapists, anti-semites, and war criminals.
This does mean that there were certainly excesses, but at the same time, you've gone straight to a non-scholarly source influenced heavily by the US government, who has been known to lie about the very subject, or try to obfuscate the real character of events.