Re: 2.6.33-rc2: Xen/Guest switching to user mode with no user page tables

[Cyrill Gorcunov <gorcunov@gmail.com>]

On Wed, Jan 06, 2010 at 03:06:05AM -0800, Christian Kujau wrote:
> On Wed, 6 Jan 2010 at 14:38, Jeremy Fitzhardinge wrote:
> > this message before, even during development.  I'd suspect either a compiler
> > bug, a miscompile, or some bad interaction with another patch.
> 
> I'm using the same compiler (gcc-4.4.2-8, binutils-2.20) for the 
> (working) 2.6.32 (Linus' git tree) and did a "make 
> distclean" to double check, but 2.6.33-rc2/3 just wouldn't boot.
> 
> > A bisection would be useful.
> 
> I'm *almost* there, only 1 or 2 revisions revisions left, I attached the 
> bisect log below. However, now this happens during "xm create" on the 
> DomU console:
> 
> ------------[ cut here ]------------
> WARNING: at /mnt/d1/linux-2.6-git/arch/x86/kernel/apic/apic_noop.c:130 
> noop_apic_write+0x40/0x50()
> Modules linked in:Pid: 0, comm: swapper Not tainted 2.6.32 #1
> Call Trace:
>  [<ffffffff81032563>] ? warn_slowpath_common+0x73/0xb0
>  [<ffffffff8101a7c0>] ? noop_apic_write+0x40/0x50
>  [<ffffffff81334160>] ? init_hw_perf_events+0x33d/0x3dd
>  [<ffffffff8100622f>] ? xen_restore_fl_direct_end+0x0/0x1
>  [<ffffffff81333cab>] ? identify_boot_cpu+0x15/0x3e
>  [<ffffffff81333dfe>] ? check_bugs+0x9/0x2e
>  [<ffffffff8132ec6e>] ? start_kernel+0x324/0x334
> ---[ end trace a7919e7f17c0a725 ]---
> 
...

This one should be fixed by the commit 125580380f418000b1a06d9a54700f1191b6e561
I believe.

	-- Cyrill