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Date: Sun, 30 Jan 2005 09:18:09 -0500 (EST)
From: Jeff Roberson <jroberson@chesapeake.net>
To: Kris Kennaway <kris@obsecurity.org>
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cc: alc@freebsd.org
cc: "David G. Lawrence" <dg@dglawrence.com>
cc: current@freebsd.org
Subject: Re: do_execve() finding vmspace_destroyed set under load
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On Sun, 30 Jan 2005, Kris Kennaway wrote:

> 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 summarily
> > > > > aborted.  What is the cause of this?
> > > >
> > > >    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 above
> > > > code happens because something failed after the process's address space
> > > > 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.
> > >
> > > Any suggestions on what to look at to try and debug this further?
> >
> >    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 occuring.
> > 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.

Whatever the problem ends up being we should probably make sure there is
some kind of reporting in this case.  We can't expect normal users to
diagnose resource shortages in this way.

>
> Kris
>