differentiate the verifier invalid mem access message error?

[Vincent Li <vincent.mc.li@xxxxxxxxx>]

Hi,

I see some verifier log examples with error like:

R4 invalid mem access 'inv'

It looks like invalid mem access errors occur in two places below,
does it make sense to make the error message slightly different so for
new eBPF programmers like me to tell the first invalid mem access is
maybe the memory is NULL? and the second invalid mem access is because
the register type does not match any valid memory pointer? or this
won't help identifying problems and don't bother ?

 4772         } else if (base_type(reg->type) == PTR_TO_MEM) {

 4773                 bool rdonly_mem = type_is_rdonly_mem(reg->type);

 4774

 4775                 if (type_may_be_null(reg->type)) {

 4776                         verbose(env, "R%d invalid mem access
'%s'\n", regno,

 4777                                 reg_type_str(env, reg->type));

 4778                         return -EACCES;

 4779                 }

and

 4924         } else {

 4925                 verbose(env, "R%d invalid mem access '%s'\n", regno,

 4926                         reg_type_str(env, reg->type));

 4927                 return -EACCES;

 4928         }