Re: pidns memory leak
From: Andrew Morton
Date: Mon Nov 02 2009 - 16:34:01 EST
On Tue, 13 Oct 2009 23:15:33 -0700
Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx> wrote:
> Daniel Lezcano [dlezcano@xxxxxxxxxx] wrote:
> > Sukadev Bhattiprolu wrote:
> >> Ccing Andrea's new email id:
> >> Daniel Lezcano [dlezcano@xxxxxxxxxx] wrote:
> >>> Following your explanation I was able to reproduce a simple program
> >>> added in attachment. But there is something I do not understand is
> >>> why the leak does not appear if I do the 'lstat' (cf. test program)
> >>> in the pid 2 context.
> >> Hmm, are you sure there is no leak with this test program ? If I put back
> >> the commit (7766755a2f249e7), I do see a leak in all three data structures
> >> (pid_2, proc_inode, pid_namespace).
> > Let me clarify :)
> > The program leaks with the commit 7766755a2f249e7 and does not leak
> > without this commit.
> > This is the expected behaviour and this simple program spots the problem.
> > I tried to modify the program and I moved the lstat to the process 2 in
> > the child namespace. Conforming your analysis, I was expecting to see a
> > leak too, but this one didn't occur. I was wondering why, maybe there is
> > something I didn't understood in the analysis.
> Hmm, There are two separate dentries associated with the processes.
> One in each mount of /proc. The proc dentries in the child container
> are freed when the child container unmounts its /proc so you don't see
> the leak when the lstat() is inside the container.
> When the lstat() is in the root container, it is accessing proc-dentries
> from the _root container_ - They are supposed to be flushed when the task
> exits (but the above commit prevents that flush). They should be freed
> when the /proc in root container is unmounted - and leak until then ?
This bug hasn't been fixed yet, has it?
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