Re: [libvirt] [PATCH 0/2] libxl: fix handling of fd and timer registrations

[Jim Fehlig <jfehlig@suse.com>]

Jim Fehlig wrote:
> Anthony PERARD wrote:
>   
>> On Mon, Feb 02, 2015 at 05:00:34PM -0700, Jim Fehlig wrote:
>>   
>>     
>>> This small series fixes some assertions we occasionally see in the
>>> libxl driver when running libvirt-TCK.  The assertions were due to
>>> races between destroying per-domain libxl_ctx and receiving fd and
>>> timer callbacks associated with them.  The races are masked by
>>> setting DEBUG loglevel in libvirtd.conf, so often missed by
>>> automated test setups that want DEBUG loglevel.
>>>
>>> Patch 1 actually fixes the assertions.  Patch2 fixes a stupid mistake.
>>> See the commit messages for details.
>>>
>>> Jim Fehlig (2):
>>>   libxl: fix fd and timer event handling
>>>   libxl: Move setup of child processing code to driver initialization
>>>
>>>  src/libxl/libxl_domain.c | 244 +----------------------------------------------
>>>  src/libxl/libxl_driver.c | 212 +++++++++++++++++++++++++++++++++++++++-
>>>  2 files changed, 212 insertions(+), 244 deletions(-)
>>>     
>>>       
>> Hi Jim,
>>
>> I gave a try to those two patches with OpenStack. Assuming I haven't make any
>> mistake, it make things worse.
>>   
>>     
>
> Thanks Anthony.  I've cooked up a simpler reproducer and will
> investigate.  I do think these patches are an improvement, but they've
> obviously uncovered a locking issue in the driver.
>   

Following Ian's suggestion, I've extended the series to drop the
per-domain libxl_ctx's altogether

https://www.redhat.com/archives/libvir-list/2015-February/msg00611.html

>   
>> Environment:
>>   Ubuntu 14.04
>>   with Xen package install (xen 4.4)
>>     

I tested the series with xen-unstable and Xen 4.4.1 + commits 2ffeb5d7,
4b9143e4, 5a968257, 60ce518a, 66bff9fd, 77a1bf37, f49f9b41, 6b5a5bba,
93699882d, f1335f0d, and 8bc64413.  If you are in a position to test the
series in a similar configuration, I'd like to hear your results.

Regards,
Jim