Linux-kernel mailing list archive 2000-06,: Re: [PATCH] kdb v1.0 for 2.3.29

# Re: [PATCH] kdb v1.0 for 2.3.29

Scott Lurndal (slurn@griffin.engr.sgi.com)
Tue, 8 Feb 2000 12:22:53 -0800 (PST)

- Messages sorted by: [ date ][ thread ][ subject ][ author ]
- Next message: Richard B. Johnson: "Copy_to_user() and locks."
- Previous message: Kanoj Sarcar: "Re: [RFC] 2.3.39 zone balancing"

>
> On Tue, Feb 08, 2000 at 11:43:23AM -0800, Scott Lurndal wrote:
> > >
> > > On Tue, Feb 01, 2000 at 09:03:23AM -0800, Scott Lurndal wrote:
> > > > This release restructures the code a bit and adds breakpoint
> > > > instruction style (int 03) breakpoints. They don't completely
> > > > work yet at this time, so as a workaround, the 'bph' command
> > > > which uses the hardware debug registers should be used to
> > > > establish breakpoints.
> > > >
> > > > There is some debug code present to save and display the contents of the
> > > > last branch register MSR on page-fault entry to the kernel.
> > > >
> > > > A list of changes and features can be found on
> > >
> > > [...]
> > >
> > > One change that I'm missing is a move of the module add code to above
> > > the module init constructor call. That makes it possible to debug
> > > crashing init_module() functions symbolically.
> >
> > Ok. I'll do that. However, by moving kdb_init() before mem_init(),
> > kdb cannot use the kernel memory allocators (It doesn't anyway, because
> > it cannot trust them, and you wouldn't be able to debug them).
>
> There must be some miscomunication. I was not proposing to change the
> kernel startup (everything is statically linked there thus all symbols
> are known anyways). What I want to change is the module loading
> (kernel/module.c:sys_init_module()). Currently the symbols for the module
> are registered to kdb after the module's init_module() function has
> run. This means you don't get a meaningfull backtrace if the init_module()
> function crashes for some reason. The change I did was to move
> the kdbaddmodsym() loop before the mod->init() call (and add a appropiate
> cleanup loop if mod->init() fails). This way it is possible to debug
> the module constructor.
>
> -Andi
>

Ah. I assumed you meant before the call to "init_modules()" in
main.c

I'll do as you suggest.

Danke,

scott

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

- Next message: Richard B. Johnson: "Copy_to_user() and locks."
- Previous message: Kanoj Sarcar: "Re: [RFC] 2.3.39 zone balancing"