Both cracks and buckling can be addressed by using various methods of structural reinforcement along with pinning, and grout and epoxy injection methods.
Merely filling a crack in a masonry building with mortar rarely works as the problem is usually an underlying issue and the integrity of the masonry units have been compromised.
Masonry units subjected to pressure or lack of adequate support are prone to cracking and buckling. This pressure can include but is not limited to:
Cracks can allow water, insects and dust into your building. They also are looked on negatively by potential buyers if you are trying to sell your building. Cracks are usually either dormant or active. Dormant meaning that they stopped widening in the past or if they are still active then the crack is still in the process of spreading. How a crack is managed and repaired depends on the condition that it is in.