Re: 2.6.29-rc1 does not boot

[Ingo Molnar <mingo@elte.hu>]

* Dieter Ries <clip2@gmx.de> wrote:

> Bisected it:
> 
> ####################################################################
> 7503bfbae89eba07b46441a5d1594647f6b8ab7d is first bad commit
> commit 7503bfbae89eba07b46441a5d1594647f6b8ab7d
> Author: Mike Travis <travis@sgi.com>
> Date:   Sun Jan 4 05:18:09 2009 -0800
> 
> cpumask: use work_on_cpu in acpi-cpufreq.c for drv_read and drv_write
> 
> Impact: use new cpumask API to reduce stack usage

thanks, this is very helpful!

Mike, most of the work_on_cpu() patches you did so far were rather 
problematic. Especially something like cpufreq can run rather early during 
bootup or during suspend/resume, so i'm not sure it's correct to rely on 
keventd for it.

I dont see anything particularly wrong in the commit itself - but 
obviously it causes this boot hang - if the bug is not found we'll revert 
it .

Also, this bit in get_cur_val():

+       if (unlikely(!alloc_cpumask_var(&cmd.mask, GFP_KERNEL)))
+               return 0;

how is that supposed to work? If we fail to allocate a cpumask we just 
ignore the call silently? That cannot be right. (but has no connection to 
this boot problem)

	Ingo