Re: [Qemu-devel] Regression on KVM qemu-system-aarch64 since "monitor: enable IO thread for (qmp & !mux) typed"

["Daniel P. Berrangé" <berrange@redhat.com>]

On Fri, Mar 23, 2018 at 12:11:17PM +0000, Peter Maydell wrote:
> On 23 March 2018 at 12:01, Auger Eric <eric.auger@redhat.com> wrote:
> > Hi,
> >
> > On 23/03/18 11:26, Peter Maydell wrote:
> >> On 23 March 2018 at 10:24, Auger Eric <eric.auger@redhat.com> wrote:
> >>> Hi,
> >>>
> >>> I observe a regression on KVM accelerated qemu-system-aarch64:
> >>>
> >>> Unexpected error in kvm_device_access() at
> >>> /home/augere/UPSTREAM/qemu/accel/kvm/kvm-all.c:2164:
> >>> 2018-03-23T09:59:59.629439Z qemu-system-aarch64: KVM_GET_DEVICE_ATTR
> >>> failed: Group 6 attr 0x000000000000c664: Device or resource busy
> >>> 2018-03-23 10:00:00.085+0000: shutting down, reason=crashed
> >>
> >> Can you get a backtrace for this? (I guess you'd need to fiddle
> >> with the kvm_device_access() code to make it assert rather
> >> than passing back the error).
> >
> > OK. I will try to do so. As I could have expected, I cannot reproduce on
> > a standalone qemu command line. The problem observed above is seen with
> > libvirt launch which may be doing some other QMP stuff concurrently?
> 
> Hmm, that could be a bit painful to debug. I dunno if libvirt
> has a "launch QEMU under gdb" option. If not, you could try

Nothing official, but the following trick should still work:

https://www.berrange.com/posts/2011/10/12/debugging-early-startup-of-kvm-with-gdb-when-launched-by-libvirtd/


Regards,
Daniel
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