Re: [Qemu-devel] Qemu: Guest Linux hangs on Mac OS X 10.11

[Aaron Elkins]

> On Oct 19, 2015, at 4:37 AM, Peter Maydell <address@hidden> wrote:
> 
> On 18 October 2015 at 20:46, Peter Maydell <address@hidden> wrote:
>> On 16 October 2015 at 08:32, Aaron Elkins <address@hidden> wrote:
>>> I built Qemu on Mac OS X 10.11 El Capitan with:
>>> 
>>>        ./configure
>>>        make
>>>        make install
>>> 
>>> Successfully.
>>> 
>>> And downloaded the official linux image, and ran it with the following:
>>> 
>>>        qemu-system-x86_64 -drive 
>>> file=linux-0.2.img,index=0,media=disk,format=raw
>>> 
>>> And then got the following warnings and the guest linux can not response to 
>>> keyboard and freezes for a period of time, and this issue repeated forever 
>>> while the guest linux was running.
>>> 
>>>        main-loop: WARNING: I/O thread spun for 1000 iterations
>>> 
>>> Any idea?
>> 
>> I've been able to reproduce this on my Yosemite system (only
>> with debugging disabled, annoyingly.) Not sure why it's doing
>> it yet, though...
>> 
>> (Note to Paolo: if I disable the 'suppress second notifications'
>> code it prints the warning forever.)
> 
> Sometimes it does manage to unwedge itself. Paolo, do you have
> any suggestions for how to debug this kind of issue? Backtraces
> and some debug printfs seem to indicate that the TCG CPU thread is sat in
> qemu_tcg_wait_io_event() until the main loop hits its "spun too
> much" check, and then the unlock-lock causes us to get out of the
> cond-wait, but then we get stuck again.
> 
> thanks
> -- PMM


Yeah, I rebuild from the source code with --enable-debug, and this bug 
disappears,
It is only buggy with debugging disabled.

Wired.

-Aaron