proc_pid_root(5) File Formats Manual proc_pid_root(5) /proc/pid/root/ - /proc/pid/root/ UNIX Linux chroot(2). exe fd/*. . ( ) . . : $ PS1='sh1# ' unshare -Urnm; sh1# mount -t tmpfs tmpfs /etc; # Mount empty tmpfs at /etc sh1# mount --bind /usr /dev; # Mount /usr at /dev sh1# echo $$; 27123 : $ PS1='sh2# ' sudo sh; sh2# ls /etc | wc -l; # In initial NS 309 sh2# ls /proc/27123/root/etc | wc -l; # /etc in other NS 0 # The empty tmpfs dir sh2# ls /dev | wc -l; # In initial NS 205 sh2# ls /proc/27123/root/dev | wc -l; # /dev in other NS 11 # Actually bind # mounted to /usr sh2# ls /usr | wc -l; # /usr in initial NS 11 /proc/pid/root ( pthread_exit(3)). (readlink(2)) ptrace PTRACE_MODE_READ_FSCREDS ptrace(2). proc(5) 3 . . : . 6.18 8 2026 proc_pid_root(5)