freeze and crashes

Alain G. Fabry alainfabry at
Fri Apr 25 20:33:59 UTC 2008

On Fri, Apr 25, 2008 at 10:47:34AM -0400, Alexander Sack wrote:

Thanks everybody for the feedback. I'm not going to bring out the champagne yet but I believe I might have found the problem.
Replaced my USB cable and now everything seems to be stable again.

I'll definitely look into the info provided below by everybody, don't want to be as frustraded as I was without having a clue what was happening.

In case the issue returns, I want to be prepared....


PS Sorry for top posting.


> Hi Alain:
> Without more details its hard to understand where your hang or freeze
> is coming from.  What I DO suggest is that you build a debug kernel
> and/or minimally enable the kernel debugger (DDB).  Then when the box
> is frozen you can get into the debugger (CTRL-ALT-ESC), type "bt", and
> post it on the list to give everybody a chance to understand what is
> hanging ("show msgbuf" as well actually).
> Here is some good documentation on how to build kernels (and debug
> ones) if you don't already know:
> Generally speaking I would enable in my KERNCONF file (GENERIC, etc.
> under src/sys/<arch>/conf/)
> # Turn off debugging symbols
> makeoptions	DEBUG=-g
> # Debugger support
> options		KDB
> options		DDB
> options		KDB_TRACE
> If you want to go further, for example you believe this is a locking
> issue then you can go whole hog and do:
> # Heavy duty debugger options
> options	DEBUG_LOCKS
> options	INVARIANTS
> options	WITNESS
> Be warned that the kernel.debug KO (kernel object) will run a lot
> slower than a stock non-debug kernel (the extra metadata the kernel is
> keeping track off etc.) so there are instances where running a debug
> kernels could make a timing bug disappear or appear more/less
> frequently.  In any event, if the problem is easily reproducible, I
> whole-heartily recommend you minimally enable KDB/DDB support so you
> can dump things on the appropriate list AS WELL AS build a complete
> debug kernel that may catch the issue (you will see console messages
> including lock order reversals and other nastiness).
> Here is some good documentation about kernel debugging:
> Let us know how things go,
> -aps
> PS Make sure that new disk is good!
> On Fri, Apr 25, 2008 at 9:01 AM, Alain G. Fabry <alainfabry at> wrote:
> > Have a issue here. I've been running FreeBSD 6.3 release for about 6 months now without problem. Then last week I purchase another external HD and installed release 7.0.
> >  Everything went great for about 3 weeks. Then suddenly my 7.0 started to crash (kde freezing, sudden reboots, etc). The first time happened when I was performing a portsnap on a FreeBSD Qemu session. It came up to the point where this 7.0 installation wasn't workable anymore.
> >
> >  Since I need to work to earn money as the rest of us, I fell back to my 6.3 release external HD -> copied over my data files and now I'm starting to get the same symthoms.
> >
> >  Input/output errors, reboot when performing a simple 'man something'. -> could this be a virus or something?
> >
> >  I'm not sure how or what I can do to find out what could be the cause of this problem?
> >
> >  Is there anywhere I can find out more about debugging such strange behavior. (everything works fine and then suddenly it freezes permanently or just reboots on its own)
> >
> >
> >  Thanks,
> >
> >  PS: I'm about to reinstall the 7.0 release and hope that that will work normal again.
> >
> >  Alain
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> >
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> >
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