Re: Lockups with 4.2-rc kernels and qemu

[Ken Moffat <zarniwhoop@ntlworld.com>]

On Thu, Aug 27, 2015 at 05:52:58PM +0100, Ken Moffat wrote:
> On Thu, Aug 27, 2015 at 12:59:14PM +0100, Ken Moffat wrote:
> > On Tue, Aug 25, 2015 at 12:40:15AM +0100, Ken Moffat wrote:
> > > (Cc'ing qemu-devel, please keep me in the Cc).
> > > 
> > > TL;DR - qemu locks up my machine when I use 4.2-rc kernels.
> > > 
> > Previous mail, or at least the copy to qemu, archived at
> > https://lists.gnu.org/archive/html/qemu-devel/2015-08/msg02784.html
> > 
> > I started bisecting, but it is going to be a slow business - kernels
> > which seem to be ok after e.g. 3 hours can still lock the box.  I
> > left it running overnight, and this morning it was still up - but
> > firefox could no longer connect externally.  I eventually tracked
> > that to my logs taking the space.  But one reason the logs had
> > become so big was the following (found from this morning's restart):
> > 
> > Aug 27 09:50:28 ac4tv kernel: [  124.279813] BUG: scheduling while
> > atomic: qemu-system-x86/1789/0x00000002
> > Aug 27 09:50:28 ac4tv kernel: [  124.279819] Modules linked in:
> > psmouse i2c_piix4 asus_atk0110 microcode k10temp
> > Aug 27 09:50:28 ac4tv kernel: [  124.279828] Preemption disabled
> > at:[<ffffffff8100787c>] kvm_vcpu_ioctl+0x7c/0x580
> 
> This is definitely a *different* bug - I just tried the next kernel,
> and started to get these messages (almost 100,000 lines of them in
> the next 4 minutes) : if that had been happening a couple of weeks
> ago, I would have noticed ;-)
> 
> But, the end result is that I cannot attempt to bisect the lockups,
> this scheduling while atomic business is preventing me looking for a
> good kernel.
> 
> Has anybody had success qith qemu on an x86_64 host running a 4.2-rc
> kernel ?  Looks as if I'll have to give up, and hope that the main
> problem doe not spread to 4.1.
> 
What will (hopefully) be my last comment on this - I went back to
4.1.3 on the host, and after a couple of hours it locked up.  Maybe
in the past I have jsut been lucky.  I think in future I'll probably
stick to native builds., it seems to be less painful.

ĸen
-- 
Il Porcupino Nil Sodomy Est! (if you will excuse my latatian)
  aka "The hedgehog song"