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Date:      Sun, 30 Jan 2005 02:57:33 -0800
From:      Kris Kennaway <kris@obsecurity.org>
To:        "David G. Lawrence" <dg@dglawrence.com>
Cc:        Kris Kennaway <kris@obsecurity.org>
Subject:   Re: do_execve() finding vmspace_destroyed set under load
Message-ID:  <20050130105733.GA71626@xor.obsecurity.org>
In-Reply-To: <20050130101403.GM48777@opteron.dglawrence.com>
References:  <20050130025217.GA32612@xor.obsecurity.org> <20050130075422.GL48777@opteron.dglawrence.com> <20050130093527.GA89923@xor.obsecurity.org> <20050130101403.GM48777@opteron.dglawrence.com>

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On Sun, Jan 30, 2005 at 02:14:03AM -0800, David G. Lawrence wrote:
> > > > Needless to say, the scripts get pretty unhappy when they're summar=
ily
> > > > aborted.  What is the cause of this?
> > >=20
> > >    There are many reasons why an exec can fail - you'd need to collect
> > > more info to be able to say specifically. Speaking generally, the abo=
ve
> > > code happens because something failed after the process's address spa=
ce
> > > had been cleared, so there is no process executable image to return
> > > to. The only thing to do in that case is to kill off the process. If
> > > you're only seeing the problem under load, it is probably indicating
> > > that your running out of a kernel VM pool of some kind.
> >=20
> > Any suggestions on what to look at to try and debug this further?
>=20
>    The first thing to do is to add some kernel printf's to do_execve()
> in each of the 'if (error)' cases to determine where the error is occurin=
g.
> It's probably not worth putting them in cases prior to the 'loop through
> the list of image activators', since the vmspace isn't destroyed until
> then.
>    Once you've done that, the cause of the problem should become obvious.

Thanks.

Kris

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