Update fs.rst

Author: madaidan

Documentation/admin-guide/sysctl/fs.rst

@@ -291,6 +291,9 @@ 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.
 
+This is disabled by default as many programs (e.g. Xorg or debugging tools)
+require access to sysfs/debugfs.
+
 The kernel config option CONFIG_SECURITY_SYSFS_RESTRICT sets the default value
 of sysfs_restrict.