The goal

Rn, we gotta understand the working of the verifier and hopefully find errors.

bpf_check

This is the holy grail where it all starts.

• bpf_verifier_env is similarly the holy grail struct where it all begins.
• bpf_features I still do not fully understand this enum, although I know it talks about readonly memory and bpf streams.
• kvzalloc_obj this is a kernel malloc variant that either allocates physically contiguous memory as kmalloc, or then falls back to vmalloc that gives virtually contiguous memory. The z also zeros out stuff. _obj means type safe wrapper that auto-calculates the size.
• iarray_realloc is a genius move. It keeps in mind both the branches of an if condition and preallocates both the branches of this so no reallocation needs to be done.