[libvirt PATCH] Fix incorrect uses of g_clear_pointer() introduced in 8.1.0

[Mark Mielke]

Sounds good - thank you...

Patch is

Signed-off-by: Mark Mielke <mark.mielke at gmail.com>


On Mon, Jun 13, 2022 at 5:08 AM Ján Tomko <jtomko at redhat.com> wrote:

> On a Sunday in 2022, Mark Mielke wrote:
> >This is a partial revert of 87a43a907f0ad4897a28ad7c216bc70f37270b93.
>
> I'll drop the trailing period before pushing.
>
> >
> >The change to use g_clear_pointer() in more places was accidentally
> >applied to cases involving vir_g_source_unref().
> >
> >In some cases, the ordering of g_source_destroy() and
> >vir_g_source_unref() was reversed, which resulted in the source being
> >marked as destroyed, after it is already unreferenced.
>
> Oops, sorry I missed that during review.
>
> >This
> >use-after-free case might work in many cases, but with versions of
> >glibc older than 2.64.0 it may defer unref to run within the main
>
> s/glibc/glib/
>
> >thread to avoid a race condition, which creates a large distance
> >between the g_source_unref() and g_source_destroy().
> >
> >In some cases, the call to vir_g_source_unref() was replaced with a
> >second call to g_source_destroy(), leading to a memory leak or worse.
> >
> >In our experience, the symptoms were that use of libvirt-python became
> >slower over time, with OpenStack nova-compute initially taking around
> >one second to periodically query the host PCI devices, and within an
> >hour it was taking over a minute to complete the same operation, until
> >it is was eventually running this query back-to-back, resulting in the
> >nova-compute process consuming 100% of one CPU thread, losing its
> >RabbitMQ connection frequently, and showing up as down to the control
> >plane.
>
> Your patch is missing a sign-off
> https://libvirt.org/hacking.html#developer-certificate-of-origin
>
> Just replying to this e-mail with the Signed-off-by line is enough - no
> need to resend the patch. I'll push it with the sign-off included after
> the pipeline succeds:
> https://gitlab.com/janotomko/libvirt/-/pipelines/562139546
>
> >---
> > src/qemu/qemu_agent.c   |  3 ++-
> > src/qemu/qemu_monitor.c |  3 ++-
> > src/util/vireventglib.c | 12 ++++++++----
> > 3 files changed, 12 insertions(+), 6 deletions(-)
> >
>
> Reviewed-by: Ján Tomko <jtomko at redhat.com>
>
> Jano
>


-- 
Mark Mielke <mark.mielke at gmail.com>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20220613/50cc0568/attachment-0001.htm>