docs/127253: Error in Handbook: http://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug-ddd.html

[John Baldwin]

The following reply was made to PR docs/127253; it has been noted by GNATS.

From: John Baldwin <jhb at freebsd.org>
To: freebsd-doc at freebsd.org
Cc: Fritz Katz <frtzkatz at yahoo.com>, freebsd-gnats-submit at freebsd.org
Subject: Re: docs/127253: Error in Handbook: http://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug-ddd.html
Date: Tue, 9 Sep 2008 13:22:00 -0400

 On Tuesday 09 September 2008 12:27:19 pm Fritz Katz wrote:
 > 
 > >Number:         127253
 > >Category:       docs
 > >Synopsis:       Error in Handbook: 
 http://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug-ddd.html
 > >Confidential:   no
 > >Severity:       serious
 > >Priority:       medium
 > >Responsible:    freebsd-doc
 > >State:          open
 > >Quarter:        
 > >Keywords:       
 > >Date-Required:
 > >Class:          doc-bug
 > >Submitter-Id:   current-users
 > >Arrival-Date:   Tue Sep 09 16:30:02 UTC 2008
 > >Closed-Date:
 > >Last-Modified:
 > >Originator:     Fritz Katz
 > >Release:        7.0-RELEASE i386
 > >Organization:
 > AAArt
 > >Environment:
 > # uname -rm
 > 7.0-RELEASE i386
 > 
 > >Description:
 >    This page in the handbook appears to give bad advice:
 >       
 http://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug-ddd.html
 >     
 >         # ddd -k /var/crash/kernel.0 /var/crash/vmcore.0
 >         
 >    Is the handbook out-of-date? Has the '-k' option been removed from 'ddd'?
 > 
 >    I think the correct invocation for 'ddd' should be:
 >    
 >         # ddd --debugger kgdb kernel.debug /var/crash/vmcore.0
 >     
 >     Following instructions in the handbook results in this message: 
 >     "GDB could not be started.", and the ddd console window prints:
 >     
 >         GNU DDD 3.3.11 (i386-portbld-freebsd7.0), 
 >           by Dorothea Lutkehaus and Andreas Zeller. 
 >         ...
 >         gdb: unrecognized option '-k'
 >         Use 'gdb --help' for a complete list of options.
 > 
 >     Which appears to be correct since,
 >         # ddd --help
 >     and
 >         # gdb --help
 >     shows there is no option '-k' 
 >     _________________
 >     
 >     also, the second option, '/var/crash/kernel.0', also appears to
 >     be incorrect. That file or executable does not exist. 
 >     
 >     Is that the executable? If so, my 'kernel' is located in:
 >     
 >        # cd /usr/obj/usr/src/sys/AAART/
 >        # ls kernel*
 >          kernel  kernel.debug   kernel.symbols
 >     
 >     _________________
 > 
 >     Attempting:
 >         # ddd --core=/var/crash/vmcore.0
 >     gives this message:
 >         "/var/crash/vmcore.0" is not a core dump: File format not recognized
 >         (gdb)
 >         
 >   However, the instructions for the command line debugger, 'kgdb', on this
 >   page are OK:
 >   
 >     
 http://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug-gdb.html
 >   
 >   and the /var/crash/vmcore.0 is recognized.
 >  
 >   # cd /usr/obj/usr/src/sys/AAART/
 >   # kgdb kernel.debug /var/crash/vmcore.0 
 > >How-To-Repeat:
 > 
 > Read the handbook and attempt to follow it's instructions.
 > >Fix:
 > Replace the offending line in the Handbook with:
 > 
 >   # ddd --debugger kgdb kernel.debug /var/crash/vmcore.0
 
 I think your updates are correct.  The old usage is from FreeBSD 4.x when one 
 used 'gdb -k' rather than 'kgdb'.  Crash dumps on 4.x also left a kernel 
 image in /var/crash which explains the /var/crash/kernel.0 reference.
 
 -- 
 John Baldwin