Date: Fri, 6 Apr 2012 11:13:21 -0700 From: Devin Teske <devin.teske@fisglobal.com> To: "'gahn'" <ipfreak@yahoo.com>, "'freebsd general questions'" <freebsd-questions@freebsd.org> Subject: RE: learning freebsd kernel Message-ID: <08b701cd1420$f4e21a60$dea64f20$@fisglobal.com> In-Reply-To: <1333735492.43069.YahooMailNeo@web130205.mail.mud.yahoo.com> References: <1333735492.43069.YahooMailNeo@web130205.mail.mud.yahoo.com>
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> -----Original Message-----
> From: owner-freebsd-questions@freebsd.org [mailto:owner-freebsd-
> questions@freebsd.org] On Behalf Of gahn
> Sent: Friday, April 06, 2012 11:05 AM
> To: freebsd general questions
> Subject: learning freebsd kernel
>
> hi gurus:
>
> how could i create the core dumps on freebsd kernel? i am trying to create a
> kernel core dump on 8.1 but it didn't happen:
>
> # sysctl -w debug.kdb.panic=1
>
> well the system went panic, entered the mode db>. i did "reboot' but there was
> no core/kernel dumps under /var/crash.
>
Did you set the "dumpdev" directive in /etc/rc.conf?
% grep dumpdev /etc/defaults/rc.conf
dumpdev="NO" # Device name to crashdump to (or NO).
savecore_flags="" # Used if dumpdev is enabled above, and present.
You should set the value of dumpdev to your swap device.
You can get this value by executing the following:
awk '$3~/swap/{print $1}' /etc/fstab
Should produce something like "/dev/mfid0s1b" or "da0s1b" or "ada0s1b" or
"ad0s1b" etc. depending on your RELEASE and hardware.
If the output is, for example, "/dev/mfid0s1b", you should add the following to
/etc/rc.conf:
dumpdev="/dev/mfid0s1b"
--
Devin
> the customized kernel has those information enabled:
>
> # Debugging for use in -current
> options KDB # Enable kernel debugger support.
> options DDB # Support DDB.
> options GDB # Support remote GDB.
>
> user@host:~:$ sysctl -a | grep debug.kdb
> debug.kdb.stop_cpus: 1
> debug.kdb.trap_code: 0
> debug.kdb.trap: 0
> debug.kdb.panic: 0
> debug.kdb.enter: 0
> debug.kdb.current: ddb
> debug.kdb.available: ddb
>
>
>
> by the way, where is my gdb? on one of my company's machisne, it looks like
> this:
>
> debug.kdb.available: ddb gdb
>
> thank you all
>
> /gahn
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