Re: [Xen-devel] Can I use SGI's kdb with a dom0 pv-ops kernel?

[Bruce Edge <bruce.edge@xxxxxxxxx>]

On Wed, Jun 30, 2010 at 9:11 AM, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> wrote:

On Tue, Jun 29, 2010 at 03:05:42PM -0700, Bruce Edge wrote:
> I asked this a few weeks ago but didn't get a response, so at the risk of
> being a nag, I'll abbreviate and restate.
>
> I know there are other Xen specific debuggers, but I want to know if there's
> any reason why SGI's kdb, http://oss.sgi.com/projects/kdb, should not be
> included in a dom0 pv-ops kernel?

Upstream is integrating one that I think is in 2.6.33
or 2.6.34. So when we rev up that we will get it for free.

Which upstream source is doing this integration? I'm not seeing any reference to it on 

 http://kernelnewbies.org/Linux_2_6_33 or http://kernelnewbies.org/Linux_2_6_34

>
> While the patches apply cleanly and build, the result is that one drops into
> kdb on an oops the serial keyboard is non-functional.
> Is this a problem inherent in including an incompatible debugger, or perhaps
> just something wrong in a .config?

What is your serial setup?

Virtual direct connect via iLO. 

 

Are you using the serial console also for Xen?

Yes

 

Is the serial console that Dom0 sees usuable outside kdb?

Yes

 

As in, can you use a null modem connection and poke Dom0 via that?

Yep. The main connection to these boxes is the serial port. The kernel cmdline has "console=hvc0,115200n8" so I get boot output on it, I'm using  "exec /sbin/getty -8 38400 hvc0" to get a login on the serial console, which works fine. The 3xCtrl-A also works. 

It's only KDB that doesn't like it. It appears kdb can output to the console but cannot read from it.

These are the kdb patch files I used: (from http://oss.sgi.com/projects/kdb)

 

-r--r--r-- 1 bedge wlvusers 199234 2010-06-22 11:22 kdb-v4.4-2.6.32-common-3.bz2

-r--r--r-- 1 bedge wlvusers 136442 2010-06-22 11:22 kdb-v4.4-2.6.32-x86-3.bz2

.config changes:

CONFIG_KDB=y

CONFIG_KDB_MODULES=y

# CONFIG_KDB_OFF is not set

CONFIG_KDB_CONTINUE_CATASTROPHIC=2

>
> Does anyone else use this debugger for dom0 work ?

I haven't used it.

Thanks for the info Konrad.

-Bruce

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