[libvirt] [PATCHv2] util: fix libvirtd startup failure due to netlink error

[Eric Blake]

On 05/03/2012 09:10 AM, Laine Stump wrote:
> This solves the problem detailed in:
> 
>   https://bugzilla.redhat.com/show_bug.cgi?id=816465
> 
> and further detailed in
> 
>   https://www.redhat.com/archives/libvir-list/2012-May/msg00202.htm
> 
> A short explanation is included in the comments of the patch itself.
> 
> Even with ACK, I will wait to push this until I have verification that
> it does not break lldpad<-->libvirtd communication (if it does, I may
> need to use the nl_handle allocated during virNetlinkStartup() for
> virNetlinkEventServiceStart()).

This last paragraph needs modification to instead describe actual
testing results before you push.

> ---
>  daemon/libvirtd.c        |    6 +++++
>  src/libvirt_private.syms |    2 ++
>  src/util/virnetlink.c    |   67 +++++++++++++++++++++++++++++++++++++++++++++-
>  src/util/virnetlink.h    |    5 +++-
>  4 files changed, 78 insertions(+), 2 deletions(-)

ACK to this patch with one nit, once the testing is complete (assuming
positive test results); worth including in 0.9.12, so hopefully we get
results soon.

> + * The short version is that, without this placeholder allocation of
> + * an nl_handle that is never used, it is possible for nl_connect() in
> + * one thread to collide with a direct bind() of a netlink socket in
> + * another thread, leading to failure of the operation (which could
> + * lead to failure of libvirtd to start). Since getaddrinfo() (used by
> + * libvirtd in virSocketAddrParse, which is called quite frequently
> + * during startup) directly calls bind() on a netlink socket, this is
> + * actually a very common occurence (15-20% failure rate on some

s/occurence/occurrence/

-- 
Eric Blake   eblake at redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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