Re: pidns memory leak

[Daniel Lezcano]

Sukadev Bhattiprolu wrote:
> Still digging through some traces, but below I have some questions that 
> I am still trying to answer.
>
> > I am not sure what you mean by 'struct pids' but what I observed is:
>
> Ok, I see that too. If pids leak, then pid-namespace will leak too.
> Do you see any leaks in proc_inode_cache ?

Yes, right. It leaks too.

> > pid_2 and pid_namespace (as they are named in /proc/slabinfo) are never  
> > decremented.
> >
> > > And the pid_namespace does not seem to reproduce for me, with out the
> > > 'ls -al /proc/...' above, or with the simpler 'ns_exec' approach to
> > > creating pid namespace.
> > I tried to write a simpler program but I failed to reproduce it.
> >
> > > I am going through the code for lxc-execute, but does it remount /proc  
> > > in the container ?
> > Right, the parent does a clone(NEWMNT|NEWPID|NEWIPC|NEWUTS), wait for  
> > the child while this one (pid 1) 'execs' the lxc-init process. This  
> > program mounts /proc and fork-exec the command passed as parameter (here  
> > 'sleep 3600').
> >
> > Without this intermediate process, the leak *seems* not happening.
> >
> > If you don't access /proc/<pid>/<file>, the leak is not happening.
>
> I could not see the code for that.  Does lxc-stop unmount /proc too ?
> Or is the umount expected to happen automatically after all processes
> in the container are killed ?

The umount is expected to happen automatically. I can not access the 
container from the outside to umount /proc.
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