Messages in this thread | | | Subject | Re: [BUG] 2.6.25-rc3-mm1 kernel panic while bootup on powerpc () | From | Benjamin Herrenschmidt <> | Date | Thu, 06 Mar 2008 11:52:42 +1100 |
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On Wed, 2008-03-05 at 16:44 -0800, Andrew Morton wrote: > On Thu, 06 Mar 2008 11:03:31 +1100 > Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote: > > > > > > Yes, we are - it's the semaphore rewrite which is doing this in > > > start_kernel(). It's being discussed. > > > > > > Enabling interrupts too early on powerpc was discovered to be fatal on > > > powerpc years ago. It looks like that remains the case. > > > > Regarding these issues. I could make it non fatal and just WARN_ON, > > provided that I have a way to differentiate legal vs. illegal calls > > to local_irq_enable(). > > And local_irq_restore() and various other things.
Yes, on powerpc 64 bits, they all go down to one C function that does the lazy enable/disable, so it would be easy to deal with. 32 bits doesn't have it that simple tho.
> I'd have thought that the way to do this would be to add it to lockdep - > lockdep already has all the infrastructure and code sites to do this. > > Set some special flag saying its-ok-to-enable-interrupts-now and test that > in lockdep.
Ok.
> akpm:/usr/src/25> grep LOCKDEP arch/powerpc/Kconfig > akpm:/usr/src/25> > > losers ;)
I have lockdep patches for powerpc 32 and 64 bits. They aren't upstream yet as they need a bit more beating up and there's at least one machine that doesn't seem to like them, so I'm working on just that. That's a good idea to add the test to lockdep tho, I'll see what I can do.
> Still, doing it for > > akpm:/usr/src/25> grep -l LOCKDEP arch/*/Kconfig > arch/arm/Kconfig > arch/avr32/Kconfig > arch/mips/Kconfig > arch/s390/Kconfig > arch/sh/Kconfig > arch/sparc64/Kconfig > arch/um/Kconfig > arch/x86/Kconfig > > should give pretty good coverage.
Ben.
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