+ pidns-make-killed-children-autoreap.patch added to -mm tree

+ pidns-make-killed-children-autoreap.patch added to -mm tree

[akpm]

The patch titled
     Subject: pidns: make killed children autoreap
has been added to the -mm tree.  Its filename is
     pidns-make-killed-children-autoreap.patch

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------------------------------------------------------
From: Eric W. Biederman <ebiederm@xmission.com>
Subject: pidns: make killed children autoreap

Force SIGCHLD handling to SIG_IGN so that signals are not generated and so
that the children autoreap.  This increases the parallelize and in general
the speed of network namespace shutdown.

Note self reaping childrean can exist past zap_pid_ns_processess but they
will all be reaped before we allow the pid namespace init task with pid ==
1 to be reaped.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Louis Rilling <louis.rilling@kerlabs.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/pid_namespace.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff -puN kernel/pid_namespace.c~pidns-make-killed-children-autoreap kernel/pid_namespace.c
--- a/kernel/pid_namespace.c~pidns-make-killed-children-autoreap
+++ a/kernel/pid_namespace.c
@@ -149,7 +149,12 @@ void zap_pid_ns_processes(struct pid_nam
 {
 	int nr;
 	int rc;
-	struct task_struct *task;
+	struct task_struct *task, *me = current;
+
+	/* Ignore SIGCHLD causing any terminated children to autoreap */
+	spin_lock_irq(&me->sighand->siglock);
+	me->sighand->action[SIGCHLD -1].sa.sa_handler = SIG_IGN;
+	spin_unlock_irq(&me->sighand->siglock);
 
 	/*
 	 * The last thread in the cgroup-init thread group is terminating.
_
Subject: Subject: pidns: make killed children autoreap

Patches currently in -mm which might be from ebiederm@xmission.com are

linux-next.patch
namespaces-fix-leak-on-fork-failure.patch
connector-userns-replace-netlink-uses-of-cap_raised-with-capable.patch
cred-remove-task_is_dead-from-__task_cred-validation.patch
pidns-use-task_active_pid_ns-in-do_notify_parent.patch
pidns-guarantee-that-the-pidns-init-will-be-the-last-pidns-process-reaped.patch
pidns-make-killed-children-autoreap.patch
syscalls-x86-add-__nr_kcmp-syscall-v8.patch
c-r-procfs-add-arg_start-end-env_start-end-and-exit_code-members-to-proc-pid-stat.patch