Re: [PATCH 0/1] tty: release_one_tty() forgets to put pids

From: Tetsuo Handa
Date: Fri Apr 02 2010 - 22:40:46 EST


Oleg Nesterov wrote:
> Add cc's.
>
> On 03/31, Andrew Morton wrote:
> >
> > On Tue, 30 Mar 2010 16:31:13 +0100
> > Catalin Marinas <catalin.marinas@xxxxxxx> wrote:
> >
> > > Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> wrote:
> > > > I got below report with 2.6.33.1 .
> > > >
> > > > unreferenced object 0xde144600 (size 64):
> > > > comm "init", pid 1, jiffies 4294678101 (age 291.508s)
> > >
> > > [... snip ...]
> > >
> > > I reported similar leaks last year -
> > > http://lkml.org/lkml/2009/7/8/422. There is some analysis in the thread
> > > above of the reference counting but I couldn't figure out where it goes
> > > wrong. It looks to me like there isn't any reference to a struct pid
> > > block but its reference count is 2.
> > >
> > > There is a bugzilla entry as well -
> > > https://bugzilla.kernel.org/show_bug.cgi?id=13868
>
> OK. I do not undertand ttys, absolutely. This means the patch
> should not be applied without acks. And in fact I feel the patch
> probably fixes the symptom, not the problem. But the logic in
> disassociate_ctty() is beyond my understanding.
>
> However, I think it is easy to explain the leak.
>
> Catalin, Tetsuo, could you try this patch?
>
I confirmed using 2.6.34-rc3 that this patch solved the leak.

Thank you.

> Oleg.
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