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Date: Tue, 5 Feb 2013 11:55:19 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: Stanislaw Gruszka <sgruszka@redhat.com>
cc: Oleg Nesterov <oleg@redhat.com>, Tommi Rantala <tt.rantala@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>, Dave Jones <davej@redhat.com>,
        John Stultz <john.stultz@linaro.org>
Subject: Re: clock_nanosleep() task_struct leak
In-Reply-To: <20130205103455.GB18313@redhat.com>
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On Tue, 5 Feb 2013, Stanislaw Gruszka wrote:
> On Mon, Feb 04, 2013 at 08:32:23PM +0100, Oleg Nesterov wrote:
> > On 02/01, Thomas Gleixner wrote:
> > >
> > > B1;2601;0cOn Fri, 1 Feb 2013, Tommi Rantala wrote:
> > >
> > > > Hello,
> > > >
> > > > Trinity discovered a task_struct leak with clock_nanosleep(), reproducible with:
> > > >
> > > > -----8<-----8<-----8<-----
> > > > #include <time.h>
> > > >
> > > > static const struct timespec req;
> > > >
> > > > int main(void) {
> > > >         return clock_nanosleep(CLOCK_PROCESS_CPUTIME_ID,
> > > >                         TIMER_ABSTIME, &req, NULL);
> > > > }
> > > > -----8<-----8<-----8<-----
> > 
> > posix_cpu_timer_create()->get_task_struct() I guess...
> > 
> > Cough. I am not sure I ever understood this code, but now it certainly
> > looks as if I never saw it before.
> 
> Looks on do_cpu_nanosleep() we call posix_cpu_timer_create(), but we do
> not call posix_cpu_timer_del() at the end. Fix will not be super simple,
> since we need to care about error cases. I can cook a patch if nobody
> else want to do this.

Would be much appreciated!

Thanks,

	tglx