Re: current dom0 panic on domu launch

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Tue, Oct 20, 2009 at 09:50:45PM +0200, Manuel Bouyer wrote:
> Can you see in xenbackendd.log if xenbackendd detects the new device and
> call the scripts ? And also if xenbackendd calls the script when a
> domU is shutdown, to release the devices ?
> 
> I can't reproduce this issue on my system. There may be a race somewhere
> which cause a device destroy event to be missed, or a condition in
> a backend driver which cause it to fail to detach.

Ok, I've been able to reproduce this. This is related to the new
flush-cache support in xbd backend. A fix has been commited to HEAD,
I'll request a pullup to netbsd-5 soon. The fix is attached.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--

Index: xen/xbdback_xenbus.c
===================================================================
RCS file: /cvsroot/src/sys/arch/xen/xen/xbdback_xenbus.c,v
retrieving revision 1.20.4.1
diff -u -p -u -r1.20.4.1 xbdback_xenbus.c
--- xen/xbdback_xenbus.c        28 Sep 2009 01:25:22 -0000      1.20.4.1
+++ xen/xbdback_xenbus.c        25 Oct 2009 13:39:07 -0000
@@ -989,6 +995,7 @@ xbdback_co_cache_flush2(struct xbdback_i
        if (xbdi->xbdi_pendingreqs > 0) {
                /* event or iodone will restart processing */
                xbdi->xbdi_cont = NULL;
+               xbdi_put(xbdi);
                return NULL;
        }
        xbdi->xbdi_cont = xbdback_co_cache_doflush;