[Crash-utility] crash enhancements proposal

[Michael Holzheu]

Maneesh Soni <maneesh at in.ibm.com> wrote on 05/05/2006 09:52:32 AM:
> On Fri, May 05, 2006 at 09:34:39AM +0200, Michael Holzheu wrote:
> > crash-utility-bounces at redhat.com wrote on 05/05/2006 09:06:55 AM:
> > > > For lcrash (lkcdutils) we have a patch, which provides
> > > > functionality to create an elf core dump out of a
> > > > system crash dump. This core dump can
> > > > then be processed with gdb. We already have code to
> > > > include swap devices and files.
> > > >
> > > > Maybe that is also one option, which should be considered
> > > > here.
> > >
> > > If I am not wrong you meant, that "lcrash" is able to show user space
> > stack
> > > backtrace because the dump includes data from swap devices & files?
> > > Just wondering if you have used "crash" in the same manner?
> > >
> >
> > There exist a patch for an older version of lcrash which implements
> > the following functionality:
> >
> > * read in swap files, when you start lcrash. Something like:
> > >> lcrash System.map dump Kerntypes swap1 swap2 ....
> > The swapfiles have to be saved of course at boot time
> > after a system crash.
> >
> > * implement a core command in lcrash:
> > >> core <process ID of process XY>
> > This writes an elf core file for process XY to disk.
> >
> > After you have the core file, you can use gdb
> > to analyze the userspace problem:
> >
> > gdb XY core
> >
> > Any more questions?
>
> Thanks, I got it now. But IMHO this functionality more looks like part of

> crash dumping mechanism than crash analysis tool. In anycase it should be
> useful.

You need the infrastructure of crash or lcrash in order to
analyze kernel datastructures to generate a core dump.
So it is the easiest way to implement it in a dump analysis
tool. If you have an idenpendent library, which provides
the funcitonality of accessing kernel data structures
in a dump, you could write of course a separate
userspace tool like crashdump2core or something like
that.

Michael