Hi Matt,
When you refer to the "latest code", what is that? I don't see anything on
source forge as released code, and the
latest from the SGI site has patches up to linux-2.4.4 is that what you were
referring to?
Thanks,
Richard
-----Original Message-----
From: Matt D. Robinson [mailto:yakker@xxxxxxxxxxxxxx]
Sent: Tuesday, September 04, 2001 4:37 PM
To: Schaal, Richard
Cc: 'r1vamsi@xxxxxxxxxx'; lkcd@xxxxxxxxxxx; akale@xxxxxxxxxxxxxxxxxxxxx;
kaos@xxxxxxxxxx
Subject: Re: LKCD + KDB ?
"Schaal, Richard" wrote:
>
> I think it would be relatively simple to have the dump_init code register
a
> dump system
> function with the kernel debugger so that you could dump the system on
> demand. Note that
> not all problems are Oops related, and that a hung system, or one that is
> grossly under performing
> would be useful to get a snapshot of the activity at that time. Manual
> entry to the debugger
> and manual dump would seem to be a useful thing. - System survivability
> after such a dump would be
> nice, but not a show stopper at this point.
You should already be able to do this with dump_function_ptr in the
latest code. This should be assigned to dump_execute (at least in
the last check-in I made). So if you call that address, you'll get
the dump function pointer.
> So far as the dumping or not after an oops and entering kdb, there is a
> differentiation as to the reason
> for entering the debugger - you might derive a dump/no dump directive from
> whether you enter the debugger
> by reason of breakpoint or oops?
I'm curious, how many people drop into kdb, and then want to take a dump?
I'd think that this is very useful for developers, but not as useful for
customers who want to crash and reboot.
> I used to work for Stratus Computer - at that time, a panic or oops would
> put us into the debugger, and if we
> were successful in patching up the problem, the system could resume
> execution. In Linux, after an oops, maybe
> a "nodump" command would be useful as well to disable the dumping that
might
> normally occur.
This is fine -- I think these are all reasonable extensions to KDB, and
I can work with that developer if need be to make that happen. There's
an easy solution, one way or another.
--Matt
> Regards,
> Richard
>
> -----Original Message-----
> From: r1vamsi@xxxxxxxxxx [mailto:r1vamsi@xxxxxxxxxx]
> Sent: Monday, September 03, 2001 2:55 AM
> To: Matt D. Robinson
> Cc: richard.schaal@xxxxxxxxx; lkcd@xxxxxxxxxxx
> Subject: Re: LKCD + KDB ?
>
> When both KDB and LKCD patches are applied, we drop into KDB on an oops.
> dump_execute will be called after we exit the debugger.
>
> If all you want is to disable dump taking after exiting debugger, that is
> easy enough with editing the dump_okay flag from within the debugger (or
> add a kdb command to do this) as Matt points out. Assuming there is a good
> reason for wanting to take the dump from within the debugger, one should
> add a simple dump command to kdb, which will just call dump_execute with
> proper regs. What you could do today is to set eip to dump_execute from
> with in the kernel, editing the stack to push correct params :-) (not as
> hard as it sounds, really)
>
> However, the cleaner approach obviously is to add the kdb dump command,
> once we understand a little better why exactly would one want to dump from
> within the debugger (on an oops).
>
> Regards.. Vamsi.
>
> Vamsi Krishna S.
> Linux Technology Center,
> IBM Software Lab, Bangalore.
> Ph: +91 80 5262355 Extn: 3959
> Internet: r1vamsi@xxxxxxxxxx
>
> Please respond to "Matt D. Robinson" <yakker@xxxxxxxxxxxxxx>
>
> To: richard.schaal@xxxxxxxxx
> cc: lkcd@xxxxxxxxxxx (bcc: S Vamsikrishna/India/IBM)
> Subject: Re: LKCD + KDB ?
>
> Richard Schaal wrote:
> >
> >
> > My question is this - I have been a fan of the kernel debugger for some
> > time, and have had a bit of difficulty
> > resolving how to configure both capabilities into my kernel. I guess
> > what I'd like to have happen is to
> > have the system enter the debugger on an oops, then have the option of
> > dumping the system from the debugger, or
> > to dump the system automatically after the debugger is exited.
>
> There's no great way to do this right now. If in kdb you can set the
> field of 'dump_okay' field to FALSE, then reset it after dropping back
> from the debugger state, that'd be fine. I guess we could also add in
> something for kdb, a one-time thing, so kdb can set dump_kdb to TRUE,
> and when dump_execute() gets called, dump_kdb is checked, and if set
> to TRUE, resets it to FALSE. Then add a kdb command that sets the
> field for you ...
>
> Would that work?
>
> --Matt
>
> > What is your thinking on this? Did I goof something up in applying the
> > patches for the two features?
> >
> > Thanks,
> > Richard
> >
> > --
> > Richard.Schaal@xxxxxxxxx Intel Corporation
> > Ph: (408)765-1579 Richard Schaal
> > Mail Stop SC12-308
> > 3600 Juliette Lane
> > "I can type faster than I think!" Santa Clara, CA 95052
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