Panic: spin lock held too long when booting

[Kris Kennaway]

Mike Clarke wrote:
> I'm getting frequent panics due to spin lock held too long when booting 
> my recently built 6.3 system with an Athlon 4850e dual core processor 
> on a Foxconn 6150M2MA motherboard (GeForce 6150 and nForce 430 
> chipsets).
> 
> FreeBSD curlew.lan 6.3-STABLE FreeBSD 6.3-STABLE #2: Sat Jul 12 09:43:21 
> BST 2008     root at curlew.lan:/usr/obj/usr/src/sys/CURLEW  i386
> 
> I'd welcome any advice on how to understand and fix this. 
> 
> The panics usually happen immediately after the "Mounting local 
> filesystem" message, but sometimes just before the end of the boot 
> process.
> 
> The system goes through the motions of producing a crash dump with a 
> visible count down on the screen followed with...
> 
> Dump complete
> Automatic reboot in 15 seconds - press a key on the console to abort
> Rebooting...
> cpu_reset: Stopping other CPUs
> 
> ... then it just hangs until I do a hard reset.
> 
> The odd thing is that when I reboot there doesn't appear to be any crash 
> dump - I see the following messages:
> 
> Checking for core dump on /dev/ad4s1b...
> savecore: no dumps found
> 
> Is the lack of a dump due to some config error of mine, or an effect of 
> the spin lock problem?
> 
> Here's the head of my kernel file ...
> 
> include         GENERIC
> nocpu           I486_CPU
> nocpu           I586_CPU
> ident           CURLEW
> nooptions       COMPAT_FREEBSD4         # Compatible with FreeBSD4
> nooptions       COMPAT_FREEBSD5         # Compatible with FreeBSD5
> options         DDB
> options         KDB
> options         KDB_UNATTENDED

You should add options WITNESS also and this will probably generate 
additional debugging and/or a panic before the error occurs.

> But I'm still a bit dubious as to whether I've really managed to create 
> a debugging kernel. I was under the impression that there should be 
> some *.symbols files in the /boot/kernel directory but there aren't any 
> (or is this just a rev. 7 thing?) and the kernel directory is only 24 
> MB.
> 
> I also noticed when building the kernel there were lines like ...
> 
> objcopy --strip-debug kernel.debug kernel
> 
> ... though I do still have /usr/obj/usr/src/sys/CURLEW/kernel.debug. 
> should I be doing something with this?

You can just use it post-mortem with kgdb.

Kris