Yes, Trotsky and Trotskysm was always strongly condemned and criticized in Soviet Union while Soviet Union existed. The history of Communist party was a mandatory subject on all levels of education, and large part of it was criticism of Trotskysm.
This also applies to all other Stalin's enemies in the party, leaders of the opposition, like Kamenev and Zinoviev and Bucharin.
These people were never formally rehabilitated, until the "perestroika" in the late 1980-s,
when only Bucharin was rehabilitated. Some other victims of Stalin like
the military commanders were rehabilitated in Khrushchev time. Mass terror was condemned (to some extent) but Stalin's struggle
with rivals inside the party was not.
I do not give references (which can be easily found). Consider this as a first hand account:-)
EDIT. Comments below show that Buharin, Kamenev and Zinoviev were rehabilitated in the late 1980-s (during the "perestroika") but Trotsky was not.