Re: 2.6.15-mm4 failure on power5

Andrew Morton
2006-01-17T08:47:58Z

Ingo Molnar <mingo@elte.hu> wrote:
>
>
> * Andrew Morton <akpm@osdl.org> wrote:
>
> > > If I revert just that patch, mm4 boots fine. Its really not obvious to
> > > me at all why that patch is breaking things though...
> >
> > Yes, that is strange. I do recall that if something accidentally
> > enables interrupts too early in boot, ppc64 machines tend to go
> > comatose. But if we'd been running that code under
> > local_irq_disable(), down() would have spat a warning.
>
> perhaps it was just luck it worked so far, and the bug could have had
> worse incarnations that the current clear hang if a certain generic
> codepath is touched in a perfectly valid way. Does CONFIG_DEBUG_MUTEXES
> (or any of the other debugging options) make any noise?
>

The bug happens on the G5 too. There's nothing useful on the screen,
nothing on netconsole. Could the people whose machines have a fscking
serial port please try CONFIG_DEBUG_MUTEXES?