Documentation/filesystems/proc.rst

2172 	hidepid=	Set /proc/<pid>/ access mode.
2177 hidepid=off or hidepid=0 means classic mode - everybody may access all
2180 hidepid=noaccess or hidepid=1 means users may not access any /proc/<pid>/
2188 hidepid=invisible or hidepid=2 means hidepid=1 plus all /proc/<pid>/ will be
2197 hidepid=ptraceable or hidepid=4 means that procfs should only contain
2201 prohibited by hidepid=.  If you use some daemon like identd which needs to learn
2218 	proc /proc proc rw,relatime,hidepid=2 0 0
2220 	# strace -e mount mount -o hidepid=1 -t proc proc /tmp/proc
2221 	mount("proc", "/tmp/proc", "proc", 0, "hidepid=1") = 0
2225 	proc /proc proc rw,relatime,hidepid=2 0 0
2226 	proc /tmp/proc proc rw,relatime,hidepid=2 0 0
2231 	# mount -o remount,hidepid=1 -t proc proc /tmp/proc
2234 	proc /proc proc rw,relatime,hidepid=1 0 0
2235 	proc /tmp/proc proc rw,relatime,hidepid=1 0 0
2244 	# mount -o hidepid=invisible -t proc proc /proc
2245 	# mount -o hidepid=noaccess -t proc proc /tmp/proc
2247 	proc /proc proc rw,relatime,hidepid=invisible 0 0
2248 	proc /tmp/proc proc rw,relatime,hidepid=noaccess 0 0