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| author |   Sukadev Bhattiprolu <sukadev@us.ibm.com> | 2007-10-18 23:40:13 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-19 11:53:40 -0700 |
| commit | 3eb07c8c8adb6f0572baba844ba2d9e501654316 (patch) | |
| tree | 5c3d527f6b003b316d41119320ebd5c589c8afd0 /kernel/exit.c | |
| parent | pid namespaces: allow signalling cgroup-init (diff) | |
| download | linux-dev-3eb07c8c8adb6f0572baba844ba2d9e501654316.tar.xz linux-dev-3eb07c8c8adb6f0572baba844ba2d9e501654316.zip | |
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>
Diffstat (limited to 'kernel/exit.c')
| -rw-r--r-- | kernel/exit.c | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index d9e8e5ee9d7f..567909fd6be4 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -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) |