Re: 2.6.19-rc1 genirq causes either boot hang or "do_IRQ: cannot handle IRQ -1"

[Benjamin LaHaise <bcrl@kvack.org>]

On Fri, Oct 06, 2006 at 06:20:54PM +0200, Muli Ben-Yehuda wrote:
> On Fri, Oct 06, 2006 at 05:50:21PM +0200, Muli Ben-Yehuda wrote:
> 
> > > What happens if you boot with max_cpus=1?
> > 
> > Trying it now... woohoo, it boots all the way and stays up!
> 
> Ok, after verifying that maxcpus=1 causes the problematic changeset to
> boot, I also tried maxcpus=1 with the tip of the tree. I hit this NULL
> pointer dereference in profile_tick, with and without
> maxcpus=1. Disassembly says that get_irq_regs() is returning NULL,
> which may or may not be related to the genirq issue.

I ran into this as well and managed to bisect it to the following commit:

7d12e780e003f93433d49ce78cfedf4b4c52adc5 is first bad commit
commit 7d12e780e003f93433d49ce78cfedf4b4c52adc5
Author: David Howells <dhowells@redhat.com>
Date:   Thu Oct 5 14:55:46 2006 +0100

    IRQ: Maintain regs pointer globally rather than passing to IRQ handlers
...

		-ben
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