Не всем разрабам ядра Linux эти тайные знания доступны. Вас сегодня посвящаю: https://en.m.wikibooks.org/wiki/Grsecurity/Appendix/Grsecuri...

CONFIG_GRKERNSEC_SYSFS_RESTRICT=y

"If you say Y here, sysfs (the pseudo-filesystem mounted at /sys) and any filesystem normally mounted under it (e.g. debugfs) will be mostly accessible only by root.  These filesystems generally provide access to hardware and debug information that isn't appropriate for unprivileged users of the system.  Sysfs and debugfs have also become a large source of new vulnerabilities, ranging from infoleaks to local compromise.
There has been very little oversight with an eye toward security involved in adding new exporters of information to these filesystems, so their use is discouraged.
For reasons of compatibility, a few directories have been whitelisted for access by non-root users:
/sys/fs/selinux
/sys/fs/fuse
/sys/devices/system/cpu"