From: Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: "Serge E. Hallyn" <serge-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org>
Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org,
bonbons-ud5FBsm0p/xEiooADzr8i9i2O/JbrIOy@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 0/2] Send a SIGCHLD to the init's pid namespace parent when reboot
Date: Mon, 15 Aug 2011 16:47:44 +0200 [thread overview]
Message-ID: <20110815144744.GA9660__2045.57081820003$1313420009$gmane$org@redhat.com> (raw)
In-Reply-To: <20110814213642.GB13799-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org>
On 08/14, Serge E. Hallyn wrote:
>
> Quoting Oleg Nesterov (oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org):
> > On 08/11, Daniel Lezcano wrote:
> > >
> > > In the case of a VPS, when we shutdown/halt/reboot the container, the
> > > reboot utility will invoke the sys_reboot syscall which has the bad
> > > effect to reboot the host.
> >
> > Stupid question. Can't sys_reboot() simply kill init (and thus the whole
> > pid_ns) in this case?
>
> The goal is to be able to distinguish a request for reboot from shutdown.
> If we just kill the init, then the parent of init (the container monitor)
> cannot restart the container to emulate reboot.
OK, thanks.
What if init reports the reason it was killed?
Ignoring LINUX_REBOOT_CMD_CAD_/etc, I mean, roughly,
- add "int reboot_cmd" into struct pid_namespace
- sys_reboot(cmd) does
if (!global_namespace) {
task_active_pid_ns(current)->reboot_cmd = cmd;
sigkill_my_init();
}
- change zap_pid_ns_processes() to do
if (pid_ns->reboot_cmd) // approximately
current->exit_state = pid_ns->reboot_cmd;
Then its parent can look at status after wait(&status).
Not that I think this is very nice, but signals are not reliable.
And once again, SIGCHLD doesn't queue. And, perhaps this doesn't
matter, but sys_reboot() sends SIGCHLD and returns -EPERM, this
can confuse the container.
In any case. If you want to send a signal, please do not introduce
SA_CLDREBOOT. Please do not play with ptrace or __wake_up_parent, this
is meaningless. Just fill siginfo and send SIGCHLD unconditionally.
Oleg.
next prev parent reply other threads:[~2011-08-15 14:47 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-11 20:23 [PATCH 0/2] Send a SIGCHLD to the init's pid namespace parent when reboot Daniel Lezcano
[not found] ` <1313094241-3674-1-git-send-email-daniel.lezcano-GANU6spQydw@public.gmane.org>
2011-08-11 20:24 ` [PATCH 1/2] add SA_CLDREBOOT flag Daniel Lezcano
2011-08-11 20:24 ` [PATCH 2/2] Notify container-init parent a 'reboot' occured Daniel Lezcano
2011-08-14 16:17 ` [PATCH 0/2] Send a SIGCHLD to the init's pid namespace parent when reboot Oleg Nesterov
2011-08-11 20:24 ` [PATCH 1/2] add SA_CLDREBOOT flag Daniel Lezcano
[not found] ` <1313094241-3674-2-git-send-email-daniel.lezcano-GANU6spQydw@public.gmane.org>
2011-08-14 16:15 ` Oleg Nesterov
2011-08-14 16:15 ` Oleg Nesterov
[not found] ` <20110814161532.GA30846-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2011-08-14 16:36 ` Bruno Prémont
2011-08-14 16:36 ` Bruno Prémont
2011-08-14 17:10 ` Oleg Nesterov
[not found] ` <20110814183611.05937c96-hY15tx4IgV39zxVx7UNMDg@public.gmane.org>
2011-08-14 17:10 ` Oleg Nesterov
2011-08-11 20:24 ` [PATCH 2/2] Notify container-init parent a 'reboot' occured Daniel Lezcano
2011-08-11 21:09 ` Serge Hallyn
2011-08-11 21:30 ` Daniel Lezcano
2011-08-11 21:30 ` Daniel Lezcano
[not found] ` <4E444A04.3070403-GANU6spQydw@public.gmane.org>
2011-08-11 21:50 ` Serge Hallyn
2011-08-12 16:29 ` Serge Hallyn
2011-08-12 16:29 ` Serge Hallyn
2011-08-12 20:42 ` Daniel Lezcano
[not found] ` <4E45904F.60904-GANU6spQydw@public.gmane.org>
2011-08-12 21:13 ` Serge Hallyn
2011-08-12 21:13 ` Serge Hallyn
2011-08-12 20:42 ` Daniel Lezcano
2011-08-11 21:50 ` Serge Hallyn
[not found] ` <1313094241-3674-3-git-send-email-daniel.lezcano-GANU6spQydw@public.gmane.org>
2011-08-11 21:09 ` Serge Hallyn
2011-08-13 0:19 ` Matt Helsley
2011-08-14 16:01 ` Oleg Nesterov
2011-08-13 0:19 ` Matt Helsley
2011-08-13 14:41 ` Daniel Lezcano
[not found] ` <20110813001959.GB5777-52DBMbEzqgQ/wnmkkaCWp/UQ3DHhIser@public.gmane.org>
2011-08-13 14:41 ` Daniel Lezcano
2011-08-14 16:01 ` Oleg Nesterov
2011-08-14 16:17 ` [PATCH 0/2] Send a SIGCHLD to the init's pid namespace parent when reboot Oleg Nesterov
2011-08-14 21:36 ` Serge E. Hallyn
2011-08-15 14:47 ` Oleg Nesterov
2011-08-15 17:39 ` Serge E. Hallyn
2011-08-15 17:50 ` Daniel Lezcano
[not found] ` <20110815173940.GA19620-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org>
2011-08-15 17:50 ` Daniel Lezcano
[not found] ` <20110815144744.GA9660-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2011-08-15 17:39 ` Serge E. Hallyn
2011-08-18 23:46 ` Daniel Lezcano
2011-08-18 23:46 ` Daniel Lezcano
2011-08-19 15:24 ` Oleg Nesterov
[not found] ` <20110819152416.GA17034-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2011-08-22 12:28 ` Daniel Lezcano
2011-08-22 12:28 ` Daniel Lezcano
2011-08-22 15:44 ` Oleg Nesterov
[not found] ` <20110822154448.GA8527-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2011-08-22 16:31 ` Bruno Prémont
2011-08-22 16:31 ` Bruno Prémont
[not found] ` <20110822183134.10390b46-hY15tx4IgV39zxVx7UNMDg@public.gmane.org>
2011-08-22 17:39 ` Oleg Nesterov
2011-08-22 17:39 ` Oleg Nesterov
[not found] ` <20110822173949.GA13242-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2011-08-22 19:17 ` Bruno Prémont
2011-08-22 19:17 ` Bruno Prémont
2011-08-23 13:33 ` Oleg Nesterov
2011-08-23 14:09 ` Greg Kurz
[not found] ` <1314108566.3465.29.camel-GiB8zCg7hOfDOqzlkpFKJg@public.gmane.org>
2011-08-23 14:29 ` Oleg Nesterov
2011-08-23 14:29 ` Oleg Nesterov
[not found] ` <20110823142914.GA22593-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2011-08-24 19:44 ` Bruno Prémont
2011-08-24 19:44 ` Bruno Prémont
2011-08-25 15:37 ` Oleg Nesterov
[not found] ` <20110824214418.474b24c6-hY15tx4IgV39zxVx7UNMDg@public.gmane.org>
2011-08-25 15:37 ` Oleg Nesterov
[not found] ` <20110823133302.GA19582-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2011-08-23 14:09 ` Greg Kurz
[not found] ` <20110822211716.7c141d5c-hY15tx4IgV39zxVx7UNMDg@public.gmane.org>
2011-08-23 13:33 ` Oleg Nesterov
[not found] ` <4E524B73.3050704-GANU6spQydw@public.gmane.org>
2011-08-22 15:44 ` Oleg Nesterov
[not found] ` <4E4DA461.8030006-GANU6spQydw@public.gmane.org>
2011-08-19 15:24 ` Oleg Nesterov
[not found] ` <20110814213642.GB13799-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org>
2011-08-15 14:47 ` Oleg Nesterov [this message]
[not found] ` <20110814161707.GB30846-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2011-08-14 21:36 ` Serge E. Hallyn
-- strict thread matches above, loose matches on Subject: below --
2011-08-11 20:23 Daniel Lezcano
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