pid_namespaces(7) Miscellaneous Information Manual pid_namespaces(7) pid_namespaces - PID namespaces(7). PID PID PID. PID / PID. PID PID 1 fork(2) vfork(2) clone(2) PID . PID CONFIG_PID_NS. init ( clone(2) CLONE_NEWPID unshare(2) CLONE_NEWPID) PID 1 "init" ( init(1)). PID ( ). "init" PID SIGKILL. "init" PID. fork(2) PID ENOMEM PID "init" . /proc/pid/ns/pid setns(2) "init". unshare(2): fork(2) fork(2) ENOMEM. "init" "init" PID. PID "init" . -- kill(2)-- "init" PID "init" . ( siginfo_t si_pid sigaction(2) .) SIGKILL SIGSTOP : PID . "init" ( ). 3.4 reboot(2) "init" . reboot(2) . PID PID: PID PID (""). PID PID clone(2) unshare(2). PID . 3.7 PID 32. PID PID PID . "" . PID . : ( kill(2) nice setpriority(2) ) PID . PID PID . PID . getpid(2) PID . PID . ( init(1) PID 1) . setns(2) PID PID setns(2). getppid(2) 0. PID ( setns(2) PID) . ( ). PID . NS_GET_PARENT ioctl(2) PID ioctl_nsfs(2). setns(2) unshare(2) setns(2) PID unshare(2) CLONE_NEWPID PID . ( 4.12 PID /proc/pid/ns/pid_for_children namespaces(7).) PID PID ( getpid()) . : PID . PID: PID . unshare(2) CLONE_NEWPID . /proc/pid/ns/pid_for_children . "init" PID ( prctl(2) PR_SET_CHILD_SUBREAPER ). setns(2) unshare(2) "init" PID parent PID "init" PID . CLONE_NEWPID CLONE_* CLONE_NEWPID CLONE_THREAD. PID . proc(5) . PID ( siginfo_t sigaction(2)). PID . CLONE_NEWPID ( EINVAL) CLONE_SIGHAND ( 4.3) CLONE_VM ( 3.12). . /proc PID /proc ( /proc/pid) PID /proc . PID procfs /proc ps(1) . CLONE_NEWNS flags clone(2) unshare(2) : procfs /proc. /proc : $ mount -t proc proc /proc readlink(2) /proc/self PID procfs ( PID procfs). PID . /proc /proc/sys/kernel/ns_last_pid ( 3.3) ( PID) PID PID . PID PID PID. CAP_SYS_ADMIN ( 5.9) CAP_CHECKPOINT_RESTORE PID. PID PID . PID ( SCM_CREDENTIALS unix(7)) PID PID . . user_namespaces(7). clone(2), reboot(2), setns(2), unshare(2), proc(5), capabilities(7), credentials(7), mount_namespaces(7), namespaces(7), user_namespaces(7), switch_root(8) 3 . . : . 6.18 8 2026 pid_namespaces(7)