reset with fwcontrol -R

[Kazumaro Aoki]

From: Sean Bruno <seanbru at yahoo-inc.com>
Subject: Re: reset with fwcontrol -R
Date: Tue, 02 Mar 2010 08:11:36 -0800

>> > In recent month, the system is in good condition, but today morning,
>> > system crashed and made a crash dump.
>> (snip)
>> > # kgdb /boot/kernel/kernel vmcore.1
>> (snip)
>> > Fatal trap 12: page fault while in kernel mode
>> > current process         = 42 (fw0_taskq)
>> > panic: page fault
>> (snip)
>> > (kgdb) bt
>> (snip)
>> > #7  0xc05f6d87 in fwohci_task_dma (arg=0xc5662000, pending=1)
>> >     at /home/usr/src/sys/dev/firewire/fwohci.c:2206
>> (snip)

>> I noticed lines 2197-2199 are
>> #if 0
>> 	dump_db(sc, dmach);
>> #endif
> 
>> Are the information generated by the commented out the lines useful to
>> analyze the problem?
> 
> I've never used that code, but I think it is more debugging.  If it is
> useful for debugging this issue, I can make it a sysctl for debugging.

I found that the following sequence cause a panic with high
probability:
1. fwcontrol -R foo.dv
2. terminate fwcontrol using ctrl-c
3. start fwcontrol -R bar.dv before finishing fwcontrol -R foo.dv
The used fwcontrol command is imported from FreeBSD6R, and back-trace
of kgdb command always says line 2206 cause a panic.

I attached the log file generated by line 2198.

Can you fix the problem?
# I write send-pr when it seems to take long time in this mailing-list.


When I used fwcontrol in the original distribution (FreeBSD 7.2R/i386)
with "fwcontrol -M dv -R bar.dv", I got the error message:
  fwcontrol: main: Error opening firewire controller #0 /dev/fw0.0 in recv_data
  : Device busy
and the system does not panic.

It certainly prohibits a panic, but it also seems to prevent to show
the firewire status that is generated fwcontrol command without any
option.

I also met a panic with another sequence caused by kldunload of
firewire.ko module.  However, I usually do not kldunload, and I do not
write the details.  If you are interested in the panic, I can write
the back-trace information.

Best regards,

Kazumaro
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