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From: Don Bowman <don@sandvine.com>
To: 'Tim Robbins' <tim@robbins.dropbear.id.au>,
	Don Bowman <don@sandvine.com>
Date: Sun, 30 May 2004 22:18:34 -0400
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cc: "'current@freebsd.org'" <current@freebsd.org>
Subject: RE: sysctl lock, system lockup
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From: Tim Robbins [mailto:tim@robbins.dropbear.id.au]
> On Sun, May 30, 2004 at 04:35:55PM -0400, Don Bowman wrote:
> > From: Don Bowman [mailto:don@sandvine.com]
> > > On the console i ran 'top', but it wouldn't start,
> > > giving:
> > > 
> > > load: 0.00  cmd: top 4282 [sysctl lock] 0.00u 0.00s 0% 180k
> > > 
> > > as the status. I can't ^C it, can't ssh in.
> > > can still ping the device.
> > > 
> > > It was doing a backgound fsck from an earlier hang.
> > > 
> > > i have called panic from db, not sure if the core will
> > > work properly or not.
> > 
> > As a followup... i did get a vmcore, and matching kernel.debug,
> > if someone can suggest what i might look @?
> 
> print sysctllock (or just sysctllock.sx_xholder if you don't have a
> serial console set up.)

(kgdb) print sysctllock
$1 = {sx_object = {lo_class = 0xc070dacc, lo_name = 0xc06ce43d "sysctl
lock", 
    lo_type = 0xc06ce43d "sysctl lock", lo_flags = 3866624, lo_list = {
      tqe_next = 0xc074f9e0, tqe_prev = 0xc0747ab0}, lo_witness =
0xc0751410}, 
  sx_lock = 0xc0748e80, sx_cnt = -1, sx_shrd_cv = {
    cv_description = 0xc06ce43d "sysctl lock", cv_waiters = 0}, 
  sx_shrd_wcnt = 0, sx_excl_cv = {cv_description = 0xc06ce43d "sysctl lock",

    cv_waiters = 9}, sx_excl_wcnt = 9, sx_xholder = 0xc8ee2150}