[Dwarf-discuss] Application of DWARF to kernel analysis
Mon Nov 14 22:18:52 GMT 2005
The linker on OpenVMS has this capability. When used with the /DSF
switch, the linker writes the debugger symbol table into a separate
file. The file has the same format as an executable program, but it
contains just debugging information. At the beginning of a debugging
session, the debugger first checks for the existence of a .DSF file.
On Mon, 2005-11-14 at 19:32 -0800, Chris Quenelle wrote:
> Hi Dave,
> This is exciting. At Sun, the kernel group has invented their own
> C-structure-describing debug format (called CTF) and they
> go through the same process of merging CTF type information.
> I've been trying to find time to implement something like
> that for dwarf, and now it seems that someone else has the same
> It looks like it's based on applying a bunch of patch diffs
> to a specific version of the libdwarf source tar file.
> Isn't that going to be an ongoing maintenance issue
> for them?
> David Anderson wrote:
> > There is a new application of DWARF2 and I thought folks
> > on this list would be interested in hearing about it.
> > It recently moved to SourceForge where all can use it.
> > Cliff Wickman provided this summary at my request.
> > David Anderson, davea at sgi dot com
> > -------------
> > Converting DWARF to DWARF
> > Debugging the Linux kernel presents a need for thousands of kernel
> > structure definitions. But it is not possible to compile all the kernel
> > include files at once. So how do you collect all kernel structures?
> > Someone in an SGI class once asked then-instructor Cliff Wickman
> > why we cannot compile the kernel and its modules with -g and then
> > collect all their DWARF information into one file. The answer was
> > that we have no such tool.
> > Hence the idea for dwarfextract.
> > The program uses the DWARF consuming library routines to extract the
> > types. It eliminates duplicates. Then turns around and feeds them to
> > the DWARF producing routines. It creates a "kerntypes" file that looks
> > like an ELF binary but contains nothing but DWARF information.
> > This kerntypes file is used by the lcrash kernel debugger to
> > cast memory images as any kernel type.
> > The dwarfextract tool is part of the Linux Kernel Crash Dump (LKCD)
> > project. The project can be downloaded from sourceforge by:
> > export CVSROOT=":pserver:anonymous at cvs.sourceforge.net:/cvsroot/lkcd"
> > cvs login # Press enter (eg no password) when prompted
> > cvs -z3 co lkcd/7.X.X/lkcdutils
> > cd lkcd/7.X.X/lkcdutils ; ./configure
> > -------------
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> > Dwarf-discuss at freestandards.org
> > http://mail.freestandards.org/mailman/listinfo/dwarf-discuss
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