Re: Lockups with 4.2-rc kernels and qemu

[Ken Moffat <zarniwhoop@ntlworld.com>]

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.

ĸen
-- 
This one goes up to eleven: but only on a clear day, with the wind in
the right direction.