From owner-freebsd-current@FreeBSD.ORG  Wed Jun  2 08:13:08 2004
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 3449616A4CE
	for <current@freebsd.org>; Wed,  2 Jun 2004 08:13:08 -0700 (PDT)
Received: from freefall.freebsd.org (freefall.freebsd.org [216.136.204.21])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id 2769343D3F; Wed,  2 Jun 2004 08:13:08 -0700 (PDT)
	(envelope-from bmilekic@FreeBSD.org)
Received: from freefall.freebsd.org (bmilekic@localhost [127.0.0.1])
	i52FD8Cc043297;	Wed, 2 Jun 2004 08:13:08 -0700 (PDT)
	(envelope-from bmilekic@freefall.freebsd.org)
Received: (from bmilekic@localhost)
	by freefall.freebsd.org (8.12.11/8.12.11/Submit) id i52FD8LP043296;
	Wed, 2 Jun 2004 08:13:08 -0700 (PDT)
	(envelope-from bmilekic)
Date: Wed, 2 Jun 2004 08:13:08 -0700
From: Bosko Milekic <bmilekic@FreeBSD.org>
To: Divacky Roman <xdivac02@stud.fit.vutbr.cz>
Message-ID: <20040602151308.GA43008@freefall.freebsd.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
User-Agent: Mutt/1.4.1i
cc: current@freebsd.org
Subject: Re: uipc_socket2.c panic
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 02 Jun 2004 15:13:08 -0000


>P.S. I have a bad feeling that this happend even BEFORE mbuma... (a day
>or two before you commited that).

  Why do you have this feeling?  Was it occuring before?

  I've had one report of a similar-nature problem which I believe
  I fixed in rev 1.2 of kern_mbuf.c.  But this might be different.

  Try backing out the mbuma changes (i.e., going to -CURRENT the day
  before mbuma) to confirm whether this still occurs.

  If so, I'd also recommend trying to disable pre-emption, just so
  we can rule that out as a possibility.  To disable pre-emption:

  - edit src/sys/kern/kern_intr.c
  - go down to ithread_schedule()
  - spot this code (around line 412):

                if (do_switch &&
                    (ctd->td_critnest == 1) ) {
                        KASSERT((TD_IS_RUNNING(ctd)),
                            ("ithread_schedule: Bad state for curthread."));
                        if (ctd->td_flags & TDF_IDLETD)
                                ctd->td_state = TDS_CAN_RUN; /* XXXKSE */
                        mi_switch(SW_INVOL);
                } else {
                        curthread->td_flags |= TDF_NEEDRESCHED;
                }

  - Change above code to this:

#if 0
                if (do_switch &&
                    (ctd->td_critnest == 1) ) {
                        KASSERT((TD_IS_RUNNING(ctd)),
                            ("ithread_schedule: Bad state for curthread."));
                        if (ctd->td_flags & TDF_IDLETD)
                                ctd->td_state = TDS_CAN_RUN; /* XXXKSE */
                        mi_switch(SW_INVOL);
                } else {
#endif
                        curthread->td_flags |= TDF_NEEDRESCHED;
      /*        } */

   (leaving only the curthread->td_flags |= TDF_NEEDRESCHED line
    uncommented).

  - rebuild and install new kernel.

  I'd recommend trying to backout to JUST before mbuma before trying
  the pre-emption disable.  Let me know how it goes.

  -Bosko