[Crash-utility] mod -S and debuginfo kernel rpm

[Michael Holzheu]

Hi Dave,

Am Dienstag, den 21.04.2009, 14:32 -0400 schrieb Dave Anderson:
> ----- "Guy Streeter" <streeter at redhat.com> wrote:
> 
> > Dave Anderson wrote:
> > ...
> > > 
> > > In other words, are you suggesting that there would be
> > > "./lib" and "./usr" subdirectories in your current directory?
> > > Where the base modules would live under "./lib" and the
> > > debug modules would live under "./usr"?  (like Michael's setup)
> > > 
> > > That would be best -- it would do-able to just enhance the currently-
> > > existing "mod -S [directory]" option to do the right thing automatically
> > > when dealing with split dumpfiles.
> > > 
> > > I just want to get everybody on the same page.
> > > 
> > 
> > We can set up the directories however we need to. It's automated, so the
> > labor involved is not an issue. The result we want is to be able to do
> > symbolic debugging in loadable modules when the target kernel and
> > debuginfo packages are not "installed" on the system.
> 
> Right -- I understand.  I wasn't sure if that automated CAS system you guys
> use already did something with the kernel-debuginfo rpm -- but not with the
> kernel rpm which contains the stripped modules.  Crash needs them both.
> 
> Again, crash searches for the stripped module first, and then looks for the
> associated .debug piece either in:
> 
> (1) the same directory containing the stripped module, or
> (2) the .debug subdirectory in the same directory containing the stripped module, or
> (3) by prepending "/usr/lib/debug" onto the directory containing the stripped module
> 
> And for the proposed plan to work, option (3) would be used, i.e., where there
> would be "parallel" trees rooted from the same target directory.
> 
> > It would help also if this would "just work", either because the current
> > directory is searched or because crash could be invoked with an option
> > or env var that pointed to the location.
> 
> I'd prefer to keep the current mechanism in place, where you can
> specify a target directory to "mod -S [directory]". 
> 
> The parallel tree layout would have to be equivalent as is the case when
> both the kernel and kernel-debuginfo rpms were installed natively, but with
> a directory pre-pended onto the /lib/... and /usr/... directories.  (which
> could simply be ".")
> 
> So for example, if the target "mod -S [directory]" was specified to be ".",
> there would be "./lib/modules" and "./usr/lib/debug/lib/modules" subdirectory
> trees.  
> 
> And then "mod -S [directory]" would just work.

Doesn't this change the current behavior? Currently the search is
restricted to the directory specified with mod -S. You would change that
and search only <-S dir>/lib/modules.. and <-S dir>/usr/lib/debug/.. ?

So maybe a new prefix option (-P ?) might be better:

(4) Search stripped modules in <-P dir>/lib/modules/ and debug modules
    in <-P dir>/usr/lib/debug/lib/modules/

Michael