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Groups > linux.kernel > #1634515
| From | Oleg Nesterov <oleg@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 2/2] pid_ns: Introduce ioctl to set vector of ns_last_pid's on ns hierarhy |
| Date | 2017-05-02 18:40 +0200 |
| Message-ID | <tCJ0d-ID-1@gated-at.bofh.it> (permalink) |
| References | (3 earlier) <tAy8V-4LQ-17@gated-at.bofh.it> <tAUj7-338-19@gated-at.bofh.it> <tAUsN-36Q-11@gated-at.bofh.it> <tAUsN-36Q-9@gated-at.bofh.it> <tCJ0d-ID-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
sorry for delay, vacation...
On 04/28, Kirill Tkhai wrote:
>
> On 27.04.2017 19:22, Oleg Nesterov wrote:
> >
> > Ah, OK, I didn't notice the ns->child_reaper check in pidns_for_children_get().
> >
> > But note that it doesn't need tasklist_lock too.
>
> Hm, are there possible strange situations with memory ordering, when we see
> ns->child_reaper of already died ns, which was placed in the same memory?
> Do we have to use some memory barriers here?
Could you spell please? I don't understand your concerns...
I don't see how, say,
static struct ns_common *pidns_for_children_get(struct task_struct *task)
{
struct ns_common *ns = NULL;
struct pid_namespace *pid_ns;
task_lock(task);
if (task->nsproxy) {
pid_ns = task->nsproxy->pid_ns_for_children;
if (pid_ns->child_reaper) {
ns = &pid_ns->ns;
get_pid_ns(ns);
}
}
task_unlock(task);
return ns;
}
can be wrong. It also looks more clean to me.
->child_reaper is not stable without tasklist, it can be dead/etc, but
we do not care?
Oleg.
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Re: [PATCH 2/2] pid_ns: Introduce ioctl to set vector of ns_last_pid's on ns hierarhy Oleg Nesterov <oleg@redhat.com> - 2017-04-26 18:00 +0200
Re: [PATCH 2/2] pid_ns: Introduce ioctl to set vector of ns_last_pid's on ns hierarhy ebiederm@xmission.com (Eric W. Biederman) - 2017-04-26 18:40 +0200
Re: [PATCH 2/2] pid_ns: Introduce ioctl to set vector of ns_last_pid's on ns hierarhy ebiederm@xmission.com (Eric W. Biederman) - 2017-04-26 19:10 +0200
Re: [PATCH 2/2] pid_ns: Introduce ioctl to set vector of ns_last_pid's on ns hierarhy Oleg Nesterov <oleg@redhat.com> - 2017-04-27 18:20 +0200
Re: [PATCH 2/2] pid_ns: Introduce ioctl to set vector of ns_last_pid's on ns hierarhy Oleg Nesterov <oleg@redhat.com> - 2017-04-27 18:20 +0200
Re: [PATCH 2/2] pid_ns: Introduce ioctl to set vector of ns_last_pid's on ns hierarhy Oleg Nesterov <oleg@redhat.com> - 2017-04-27 18:30 +0200
Re: [PATCH 2/2] pid_ns: Introduce ioctl to set vector of ns_last_pid's on ns hierarhy Oleg Nesterov <oleg@redhat.com> - 2017-05-02 18:40 +0200
Re: [PATCH 2/2] pid_ns: Introduce ioctl to set vector of ns_last_pid's on ns hierarhy ebiederm@xmission.com (Eric W. Biederman) - 2017-05-02 19:30 +0200
Re: [PATCH 2/2] pid_ns: Introduce ioctl to set vector of ns_last_pid's on ns hierarhy ebiederm@xmission.com (Eric W. Biederman) - 2017-05-02 23:30 +0200
Re: [PATCH 2/2] pid_ns: Introduce ioctl to set vector of ns_last_pid's on ns hierarhy ebiederm@xmission.com (Eric W. Biederman) - 2017-04-27 18:50 +0200
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