PowerMac G5 boot hangups before Copyright notice: "Stopped at 0: illegal instruction 0" [10.1-BETA1 example]

[Mark Millard]

Using 10.1-BETA1 I added "options DDB" and "options GDB" to powerpc64's GENERIC64. (I also used WITH_DEBUG_FILES=, WITHOUT_CLANG=, and WITH_DEBUG= in /etc/make.conf.) So buildworld, kernel was basically just set up to have more of a debugging context around (including for any ports builds).

The result was new information about the PowerMac G5 boot hangups: The screen is no longer blank when the G5 is hung up without there being a Copyright notice yet. It says...

> GDB: no debug ports present
> KDB: debugger backends: DDB
> KDB: current backend: DDB
> [ thread pid -1 tid 1006665719 ]
> Stopped at 0: illegal instruction 0
> db>

(I had no ability to input at that point.) Normally the Copyright notice would have displayed instead of "[...]" and what follows. (I do not claim to have all the spacing, capitalization, and such correct above.)

That text is constant from hang to hang when it hangs just before it would normally output the Copyright notice: The numbers do not vary, much less the other text. It has never failed until after the two KDB messages are present. So far I've only tested one PowerMac G5, booting over and over for a few hours.



(I do not claim to be set up for remote kernel debugging. I just decided to let GDB go along for the ride when I added DDB.)

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Mark Millard
markmi at dsl-only.net