GC interaction with malloc/free

[DLearner via Digitalmars-d-learn]

Suppose there is a D main program (not marked anywhere with 
@nogc), that _both_

A: Calls one or more C functions that themselves call 
malloc/free; and also
B: Calls one or more D functions that themselves call malloc/free 
via `import core.stdc.stdlib;`

Assuming the malloc/free's are used correctly, does this 
situation risk crashing the D main program?

Best regards