2007-05-19 07:16:13

by Darren Hart

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Subject: maxcpus=1 fails to boot

When trying to boot with the maxcpus=1 option, the -rt kernel seems to hang
somewhere in acpi_processor_init().

I tested mainline 2.6.21 and it does boot with maxcpus=1. 2.6.20-rt8,
2.6.21-rt1, 2, and 4 all hang at:

Calling initcall 0xffffffff817a41df: acpi_processor_init+0x0/0xdf()

when booted with initcall_debug and maxcpus=1. I traced this only as far as
the call to acpi_bus_register_driver. So this seems to have been introduced
by the -rt patch. I'm not sure if I should try and see when it was
introduced (as 2.6.16-rt22 does not fail) or if I should head "down the acpi
rabbit hole"...

Thanks,

--
Darren Hart
IBM Linux Technology Center
Realtime Linux Team


2007-05-19 08:57:01

by Thomas Gleixner

[permalink] [raw]
Subject: Re: maxcpus=1 fails to boot

On Sat, 2007-05-19 at 00:15 -0700, Darren Hart wrote:
> When trying to boot with the maxcpus=1 option, the -rt kernel seems to hang
> somewhere in acpi_processor_init().
>
> I tested mainline 2.6.21 and it does boot with maxcpus=1. 2.6.20-rt8,
> 2.6.21-rt1, 2, and 4 all hang at:
>
> Calling initcall 0xffffffff817a41df: acpi_processor_init+0x0/0xdf()
>
> when booted with initcall_debug and maxcpus=1. I traced this only as far as
> the call to acpi_bus_register_driver. So this seems to have been introduced
> by the -rt patch. I'm not sure if I should try and see when it was
> introduced (as 2.6.16-rt22 does not fail) or if I should head "down the acpi
> rabbit hole"...

Be careful, when sticking your head into this hole !

I try to nail it down.

tglx