Re: there is a bug in twe driver or disk subsystem for sure

> The 3ware (twe) driver is obviously not causing this panic.
> It's something else (at line 128 in file /usr/src/sys/udm_dbg.c).

I do not insist on driver causing the panic.  I may or 
maynot be related to twe driver but it seems like it is
related to the disk io subsystem (which includes
the driver, kernel stuff and the hardware and maybe
something else). It think so because it happens ONLY
when some heavy disk usage is happenning or when
hot swap disk is pull out of the bay. The box has ONLY
hotswap disk and all of them connected to 8506-4LP
in hot swap bays. FreeBSD is installed on that array (is
is RAID 5). 

I unsterstand that error message related to ot being able
to delete a busy unit is okay. However nobody 
explained why 'stray irq9'. Anyhow, that is no the main
problem. IT is not a problem at all because it happenes
only when i shutdown the system and i do not want it be
shutdown ever :) It is supposed to be run forever and ever.
Which i cannot get from it yet.

Currently I am running GENERIC kernel. If DIAGNOSTIC is
ON there then i have it ON. Otherweise it is off and i will try
truning it on on monday.

I will gladly send you the mentioned stack trace if you explain
to me what i must do in the debugger to obtain it. I am not good
at the kernel debugger. I know C and for the last 5 years i am mostly
perl programmer. :)

And what is this udm_dbg.c file? Is it really related to the problem?
What is it for? What is UDM anyway? And why udm_dbg.c and
not just udm.c ? Is it this a debug version? I just want to know.

Best regards and i hope we all will figure this problem out and make
FreeBSD 5.2 STABLE :)

> Memory modified after free 0x788f400(508) val=20202020 _at_ 0xe788f400
> panic: Most recently used by devbuf
> at line 128 in file /usr/src/sys/udm_dbg.c
> cpu=0;
> Debugger ("panic")
> Stopped at Debugger +0.46: xchgl %ebx, in_Debugger.0
> and i typed 'c' in debugger: