RE: Capturing dmesg upon system crash on 6.3

On Monday 25 February 2008 13:32:01 Yehonatan Yossef wrote:
I'm facing a system reboot upon loading of the driver, and

I could use

a tool for capturing dmesg upon system crash (such as
netconsole
on Linux).

Your kernel isn't setup for driver development:
http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-ha
ndbook/kerneldebug.html
http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kern
elconfig.html

Basically, your system is rebooting cause the kernel panics and
you're not setup for crash dumps, or anything that could help you
diagnose the panic.
--
Mel

I've setup the dumpdev/dumpdir and I get a vmcore image
upon a crash.

I don't really understand how to use kgdb in order to read
it but more
than that - I don't need that much of data. I only want the dmesg
report at the moment, see at what point my driver went
crazy. Is it possible?


Uhm, no. Fundamental logic flaw: when a kernel is stopped,
you can't issue userland commands. All you have when you use
ddb, is the contents of the registers, ram and backtrace.

You really want ddb in the kernel: when a kernel panics,
it'll drop to ddb and you can examine registers and do a
backtrace, instead of dumping core and rebooting. It should
point exactly to where your driver went crazy.
--
Mel


I meant making the dmesg log sent over the network/serial console to a
linux machine. I just found out about syslogd, I'm trying to figure out
how to use it.
DDB sounds like a great option for deeper debugging, I'll use it.

Yony
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