I still met the above issue on rhel6.1 with libvirt-0.8.7-18.el6.src.rpm when I used lcov to test libvirt codes coverage by virsh command.

Please see attachment for reproduce steps.

Created attachment 502781 [details]
details

Since we can't detect which messages come from qemu, we are filtering out libvirt debug messages to get qemu's output. In your case there's a lot of noise in the log file that is not filtered out, which results in the error.

These messages causing problems come from 'lcov', which is a test coverage program. This is not something that is ever enabled in production builds shipped by OS distros. We already filter out debug messages libvirt generates, and if QEMU ever generates too much debug output on startup, QEMU would need fixing. So I don't consider there to be an outstanding libvirt bug to deal with here, since using 'lcov' is not a real world scenario.

(In reply to comment #6)
> These messages causing problems come from 'lcov', which is a test coverage
> program. This is not something that is ever enabled in production builds
> shipped by OS distros. We already filter out debug messages libvirt generates,
> and if QEMU ever generates too much debug output on startup, QEMU would need
> fixing. So I don't consider there to be an outstanding libvirt bug to deal with
> here, since using 'lcov' is not a real world scenario.

Hi Daniel,
Thanks for your comment, I know you mean. 

Unfortunately, it's a bad news for libvirt QE, we want to add some 'effective' test cases to cover libvirt source code according to lcov test result, now, it seems we can't do that.

BTW, KVM QE also use 'lcov' to test qemu/kvm and kernel code coverage, however, they haven't met this kind of case, so I think it's not a qemu issue.


Alex

NB Those lcov messages are telling you that lcov can't create its data files. If you solve the problems lcov is reporting, then those messages wouldn't be polluting the logs either, and everything would still work.

Alex, Daniel is telling you that you have a problem with your configuration of the lcov tool which is causing the behavior you've reported here as a bug against libvirt.  You need to fix your lcov configuration so that it doesn't log large numbers of messages similar to:

profiling:/root/rpmbuild:Cannot create directory
profiling:/root/rpmbuild/BUILD/libvirt-0.8.7/src/.libs/libvirt_util_la-authhelper.gcda:Skip

which are filling up libvirt's buffer.  Agreed that this is neither a libvirt nor a qemu bug.

(In reply to comment #9)
> Alex, Daniel is telling you that you have a problem with your configuration of
> the lcov tool which is causing the behavior you've reported here as a bug
> against libvirt.  You need to fix your lcov configuration so that it doesn't
> log large numbers of messages similar to:
> 
> profiling:/root/rpmbuild:Cannot create directory
> profiling:/root/rpmbuild/BUILD/libvirt-0.8.7/src/.libs/libvirt_util_la-authhelper.gcda:Skip
> 
> which are filling up libvirt's buffer.  Agreed that this is neither a libvirt
> nor a qemu bug.

Hi Daniel and Dave,
I am trying to avoid these error information from lcov, thanks for your nice comments.


Alex