Re: add DIAGNOSTIC back to GENERIC/INSTALL

[David Young <dyoung%pobox.com@localhost>]

On Fri, Jun 17, 2011 at 12:34:53PM +0200, Manuel Bouyer wrote:
> On Fri, Jun 17, 2011 at 12:24:13PM +0200, Adam Hamsik wrote:
> > 
> > On Jun,Thursday 16 2011, at 5:30 PM, Mindaugas Rasiukevicius wrote:
> > > - DDB_ONPANIC=1 and DDB_COMMANDONENTER="bt;show regsisters" and perhaps
> > >  also "call ddb_vgapost" in the beginning (not sure if there are any
> > >  potential side effects?).  Otherwise, not getting information from DDB
> > >  is just counter-productive, plus we get not very useful reports, when
> > >  backtrace is missing.
> > 
> > I like this we should definitely set DDB_COMMANDONENTER to something like 
> > above.
> 
> be carefull though; this can easily output more than the 25 lines of a VGA
> display; and so usefull information (like the panic message) may have
> dissapeared. 

It can also lead to an infinite loop where a fault while ddb examines
the stack for 'bt' leads ddb to execute 'bt;show registers' again which
leads to another fault.  Just another reason to be careful.

Dave

-- 
David Young             OJC Technologies
dyoung%ojctech.com@localhost      Urbana, IL * (217) 344-0444 x24