Bug#592487: linux-image-2.6.32-5-xen-686: dump

[Ian Campbell <ijc@hellion.org.uk>]

On Tue, 2010-08-10 at 16:07 +0300, root wrote:
> Package: linux-2.6
> Version: 2.6.32-18
> Severity: normal

Thanks for the report.

> [    0.004000] ------------[ cut here ]------------
> [    0.004000] WARNING: at /build/buildd-linux-2.6_2.6.32-18-i386-HNrmOz/linux-2.6-2.6.32/debian/build/source_i386_xen/arch/x86/xen/enlighten.c:731 perf_events_lapic_init+0x28/0x29()
> [    0.004000] Hardware name: VirtualBox

This is a Xen domain 0 running in VirtualBox?

> [    0.004000] Modules linked in:
> [    0.004000] Pid: 0, comm: swapper Not tainted 2.6.32-5-xen-686 #1
> [    0.004000] Call Trace:
> [    0.004000]  [<c10370a5>] ? warn_slowpath_common+0x5e/0x8a
> [    0.004000]  [<c10370db>] ? warn_slowpath_null+0xa/0xc
> [    0.004000]  [<c1011bb0>] ? perf_events_lapic_init+0x28/0x29
> [    0.004000]  [<c140307d>] ? init_hw_perf_events+0x2dd/0x376
> [    0.004000]  [<c1402cd0>] ? check_bugs+0x8/0xd8
> [    0.004000]  [<c13fb7fe>] ? start_kernel+0x309/0x31d
> [    0.004000]  [<c13fd3c3>] ? xen_start_kernel+0x615/0x61c
> [    0.004000]  [<c1409045>] ? print_local_APIC+0x61/0x380
> [    0.004000] ---[ end trace a7919e7f17c0a725 ]---

I think that is because Xen doesn't expose any APICs to the guest, but
tries to arrange for nothing to use it by hooking in at a higher layer.
It has a WARN_ON in its APIC write function to try and catch stray
writes.

I think the warning in this instance is likely to be harmless, although
obviously it means that perf will not work (which it wouldn't anyway
under Xen).

Ian.

-- 
Ian Campbell

Dismissed.  That's a Star Fleet expression for, "Get out."
		-- Capt. Kathryn Janeway, Star Trek: Voyager, "The Cloud"