Re: [PATCH] pid: Extend/Fix pid_vnr

[ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)]

"Serge E. Hallyn" <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> writes:

> Quoting sukadev-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org (sukadev-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org):
>> Oleg Nesterov [oleg-6lXkIZvqkOAvJsYlp49lxw@public.gmane.org] wrote:
>> | On 12/05, Eric W. Biederman wrote:
>> | > 
>> | > +pid_t pid_vnr(struct pid *pid)
>> | > +{
>> | > +	return pid_nr_ns(pid, current->nsproxy->pid_ns);
>> | > +}
>> 
>> Hmm. current->nsproxy be NULL during process exit ?
>> So this safe as long as pid_vnr() is not called after a
>> process exits its namespaces. Probably no such callers atm. 
>
> Yes I did a little audit for those this morning bc I frankly didn't
> believe there weren't any.  But I couldn't find any :)

Cool.  The only case pid_vnr would make sense in that context is if
we were talking to user space after we had exited our namespaces.
Which is at least as stretch.

Eric