Re: Reboot instead of debugger/dump from X11? (Re: an accidental way to pull the plug)

On Sat, 25 Dec 2004, Robert Watson wrote:
> On Sat, 25 Dec 2004, Chuck Robey wrote:
>
>> I got a little too fast just now, and did something that I shouldn't
>> have done, but what's interesting is, FreeBSD decided to pull the plug
>> and instantly reboot, which is usually something to be regarded as
>> pathological, so I am letting you folks know.  I haven't analyzed
>> exactly what happened to cause it, actually.
>
> With the recent 802.11 panic I posted about a bit earlier, I saw something
> rather odd: when the panic took place on the normal text console, the
> system dropped to the debugger.  However, when it took place with X11
> running, I got an "instant reboot" -- no dump, etc.  So something odd is
> happening during even normal failure modes when X11 is running for me.  I
> wonder if anyone else is seeing this?

   Just a "me too" for observing exactly the same symptom on a Thinkpad R40.
At the first time I thought the reboot-without-panic-to-ddb was associated 
with improper kernel debug settings; however, after lots of fscking and
rebooting, I finally realised that all I have to do is to disable xdm
on startup and switch back to the text console. And yes, the panic was
from if_wi.

   According to sys/ddb/db_main.c:195, it appears that the panic would
never get into ddb if the console is unavailable. I'm curious about
whether the doadump() would also be suppressed or not at that moment?

> Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
> robert_at_fledge.watson.org      Principal Research Scientist, McAfee Research
>
>
>>
>> Anyhow, I have been using FreeBSD as a fine platform for a Free database I
>> am constructing for a buddy of mine who has a video rental store.  The
>> database, which was active at the time (the app is nearly complete) is
>> made with Python, gtk, pygtk (obviously) and the Sleepycat database.  I
>> called those folks up and got the opinion that, as long as I didn't try to
>> distribute the software, the way I'm handling it (for free) it generally
>> falls under their free license, so I'm ok on that.
>>
>> Anyhow, I was talking screen dump pictures of the 6 data entry screens, in
>> X11, using xv to grab the windows.  I got a bit confused with mouse
>> clicks, and actually asked it to do a grab while another grab was in delay
>> wait (it has a timer delay, which I set to 5 seconds).  Result: reboot,
>> instant.
>>
>> I think that's it, although I will try to answer any questions.  If you
>> folks are all too tied up with your own projects, it won't bother me, I'm
>> only trying to be conscientious about things.
>>
>> ----------------------------------------------------------------------------
>> Chuck Robey         | Interests include C & Java programming, FreeBSD,
>> chuckr_at_chuckr.org   | electronics, communications, and SF/Fantasy.
>>
>> New Year's Resolution:  I will not sphroxify gullible people into looking up
>> fictitious words in the dictionary (on the wall at my old fraternity,
>> Signa Phi Nothing).