Messages in this thread |  | | | Date | Thu, 2 Jul 2009 11:15:49 -0500 | | From | "Serge E. Hallyn" <> | | Subject | Re: [PATCH][BUGFIX] cgroups: fix pid namespace bug |
Quoting Paul Menage (menage@google.com): > On Thu, Jul 2, 2009 at 6:26 AM, Serge E. Hallyn<serue@us.ibm.com> wrote: > > Quoting Li Zefan (lizf@cn.fujitsu.com): > >> Paul Menage wrote: > >> > On Wed, Jul 1, 2009 at 7:17 PM, Li Zefan<lizf@cn.fujitsu.com> wrote: > >> >> But I guess we are going to fix the bug for 2.6.31? So is it ok to > >> >> merge a new feature 'cgroup.procs' together into 2.6.31? > >> >> > >> > > >> > Does this bug really need to be fixed for 2.6.31? I didn't think that > >> > the namespace support in mainline was robust enough yet for people to > >> > use them for virtual servers in production environments. > > > > I don't know where the bar is for 'production environments', but I'd > > have to claim that pid namespaces are there... > > Well, pid namespaces are marked as experimental, as are user > namespaces (and were described as "very incomplete" a few months
incomplete (due to signaling issues which have mostly been resolved) but stable and usable.
user namespace are a completely different story :)
> back). Pid namespaces are useful for process migration (which is still > under development) or virtual servers (for which user namespaces are > pretty much essential). So I'm not sure quite what you'd use pid > namespaces for yet.
You don't need user namespaces to use pid namespaces for virtual servers (depending on your use).
Now the fact remains this is a hard to trigger bug which doesn't corrupt the kernel, and - to take back what I said earlier - userspace can work around it by simply freezing the cgroup before reading its tasks file.
So I guess I can go either way... If Li's patch were more complicated I'd definately be for waiting. But I do object to the general process of making a fix of a pretty bad bag depend on an unrelated new feature!
-serge
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