pid namespaces: destroy pid namespace on init's death

Terminate all processes in a namespace when the reaper of the namespace is
exiting.  We do this by walking the pidmap of the namespace and sending
SIGKILL to all processes.

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Sukadev Bhattiprolu 2007-10-18 23:40:13 -07:00 committed by Linus Torvalds
parent 0fbc26a6cf
commit 3eb07c8c8a
3 changed files with 65 additions and 1 deletions

View file

@ -879,7 +879,32 @@ static inline void exit_child_reaper(struct task_struct *tsk)
if (likely(tsk->group_leader != task_child_reaper(tsk)))
return;
panic("Attempted to kill init!");
if (tsk->nsproxy->pid_ns == &init_pid_ns)
panic("Attempted to kill init!");
/*
* @tsk is the last thread in the 'cgroup-init' and is exiting.
* Terminate all remaining processes in the namespace and reap them
* before exiting @tsk.
*
* Note that @tsk (last thread of cgroup-init) may not necessarily
* be the child-reaper (i.e main thread of cgroup-init) of the
* namespace i.e the child_reaper may have already exited.
*
* Even after a child_reaper exits, we let it inherit orphaned children,
* because, pid_ns->child_reaper remains valid as long as there is
* at least one living sub-thread in the cgroup init.
* This living sub-thread of the cgroup-init will be notified when
* a child inherited by the 'child-reaper' exits (do_notify_parent()
* uses __group_send_sig_info()). Further, when reaping child processes,
* do_wait() iterates over children of all living sub threads.
* i.e even though 'child_reaper' thread is listed as the parent of the
* orphaned children, any living sub-thread in the cgroup-init can
* perform the role of the child_reaper.
*/
zap_pid_ns_processes(tsk->nsproxy->pid_ns);
}
fastcall NORET_TYPE void do_exit(long code)