What would perror() be in the kernel? I can't tell what the error codes are from the error values ,i.e -22 alone.
The Linux kernel just uses negated errno codes as a convention. So look in asm-generic/errno-base.h or asm-generic/errno.h and find...
#define EINVAL 22 /* Invalid argument */
This can happen if you pass NULL to a function that doesn't accept NULL, for example. It depends on the function.
perror, but it's about how to interpret error codes in the kernel. The perror function is only available in userspace, it's not available in the kernel - Dietrich Epp 2017-06-07 19:18
perror(), not about the meaning of the error codes. So this is not a good answer - user3629249 2017-06-07 14:40