Re: 2.6.30-rc8 Oops whilst booting

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Mon, 2009-06-08 at 09:21 -0700, Linus Torvalds wrote:
> 
> On Mon, 8 Jun 2009, Chris Clayton wrote:
> > 
> > OK. I reversed that change and built and installed the kernel. It has
> > withstood 100 reboots without a panic. Additionally, I pulled the
> > latest changes (that will be rc8-git5, I think) from kernel.org,
> > reversed the change to that kernel and built and installed it. That
> > too withstood 100 reboots without a panic.
> > 
> > Let me know if there's anything else I can do to help fix this.
> 
> That's already pretty convincing.
> 
> James, Arjan? The original oops message is here (a jpg screen capture, 
> unable to open initial console):
> 
> 	http://lkml.org/lkml/2009/6/6/142
> 
> and it's this bug entry:
> 
> 	Bug-Entry       : http://bugzilla.kernel.org/show_bug.cgi?id=13474
> 	Subject         : Oops whilst booting
> 	Submitter       : Chris Clayton <chris2553@googlemail.com>
> 	Date            : 2009-06-06 18:59 (2 days old)
> 	References      : http://marc.info/?l=linux-kernel&m=124431487924254&w=4
> 
> and now bisected down to 
> 
> >> commit d5a877e8dd409d8c702986d06485c374b705d340
> >> Author: James Bottomley <James.Bottomley@HansenPartnership.com>
> >> Date:   Sun May 24 13:03:43 2009 -0700
> >>
> >>     async: make sure independent async domains can't accidentally entangle
> 
> please advice. Otherwise I'll have to revert.

The root cause is a reordering of the devices caused by the async code.

I suspect it's a bug in async that was obscured by the old behaviour of
async_synchronize.. (or it's a bug in the new code) ... how long do I
have to find out which?

James