kernel panic in usb0; was: RE: using vkbd device

[Norbert Koch]

> >In gdb "bt" only shows two entries. The function where the panic
> >occurred and 0x0!
> >
> >
>
> that is normal
> you don't want to jump into gdb that soon.
> there is hardly anything set up.
>
> use the sysctl to enter gdb later.
>
> >BTW, after boot -gd, when gdb attaches I have a kernel panic too.
> >But I can just enter "continue" and the kernel continues booting.
> >Is that ok?
> >
> >
>
> what do you mean "panic"?
> I never use -gd, just -g
>
> then hitting ^ALT-ESC  or using th esysctl makes me enter the debugger
> when I need to.
>
>
>

Ok,
may be, I am doing something stupidly wrong.

1. Added DIAGNOSTIC, USB_DEBUG, INVARIANT_SUPPORT, INVARIANTS to my
configuration
   and installed a new debug kernel.
2. Booted the target to the loader prompt.
   "unload kernel"
   "load kerneld"
   "boot -gd"
3. "gdb -k kernel.debug" & "target remote /dev/cuaa0" on my workstation.
4. Arrived in Debugger() and pressed "c".
5. The kernel booted. I saw the usual boot messages.
   After seeing "IP filtering initialized...", I saw:
   "panic: usb_cold_explore: busses to explore when !cold".
6. Found, that cold is indeed 0.
7. Booted again up to 4. and set a breakpoint at usb_cold_explore().
   Pressed "c" and got (from gdb):
     Continuing.
     Cannot insert breakpoint 1:
     Cannot access memory at address 0xc01e5a37.
   At the same time the target console showed twice:
   "Fatal trap 12: page fault..."
   "..."
   "supervisor read, page not present"
   "..."

So, do I have something very wrong in my kernel configuration? (See attached
file)
What about HZ=400 and NO_SWAPPING? Any known problems?
Can't I set a breakpoint at that early stage of booting?

Thanks for any help,

Norbert
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