[PATCH v2 00/13] resolve hangs/crashes on libvirtd shutdown

[Nikolay Shirokovskiy]

Pushed now.  Thanx everyone for review.

Patch "[PATCH v2 05/13] rpc: add virNetDaemonSetShutdownCallbacks" does not have mantainer 
review but I guess it is ok as the patch is simple enough and it's API is used in other
patches of series.

I would also want to note that crashes are still possible because not all threads
are joined on shutdown in qemu driver and other drivers. For example in qemu driver we 
spawn a thread during fake reboot or on daemon startup we spawn threads for every
VM to reconnect. So I would like to continue to work on this issues. Is this considered
worth the effort? I realize these are rare corner cases, like daemon shutdown immediately
after daemon start or daemon shutdown coincide with some domain reboot etc.

Nikolay

On 23.07.2020 13:14, Nikolay Shirokovskiy wrote:
> I keep qemu VM event loop exiting synchronously but add code to avoid deadlock
> that can be caused by this approach. I guess it is worth having synchronous
> exiting of threads in this case to avoid crashes.
> 
> Patches that are already positively reviewed has appropriate 'Reviewed-by' lines.
> 
> Changes from v1:
> - rename stateShutdown to state stateShutdownPrepare
> - introduce net daemon shutdown callbacks
> - make some adjustments in terms of qemu per VM's event loop thread
>   finishing
> - factor out net server shutdown facilities into distinct patch
> - increase shutdown timeout from 15s to 30s
> 
> Nikolay Shirokovskiy (13):
>   libvirt: add stateShutdownPrepare/stateShutdownWait to drivers
>   util: always initialize priority condition
>   util: add stop/drain functions to thread pool
>   rpc: don't unref service ref on socket behalf twice
>   rpc: add virNetDaemonSetShutdownCallbacks
>   rpc: add shutdown facilities to netserver
>   rpc: finish all threads before exiting main loop
>   qemu: don't shutdown event thread in monitor EOF callback
>   vireventthread: exit thread synchronously on finalize
>   qemu: avoid deadlock in qemuDomainObjStopWorker
>   qemu: implement driver's shutdown/shutdown wait methods
>   rpc: cleanup virNetDaemonClose method
>   util: remove unused virThreadPoolNew macro
> 
>  scripts/check-drivername.py   |   2 +
>  src/driver-state.h            |   8 ++++
>  src/libvirt.c                 |  42 ++++++++++++++++
>  src/libvirt_internal.h        |   2 +
>  src/libvirt_private.syms      |   4 ++
>  src/libvirt_remote.syms       |   2 +-
>  src/qemu/qemu_domain.c        |  18 +++++--
>  src/qemu/qemu_driver.c        |  32 +++++++++++++
>  src/qemu/qemu_process.c       |   3 --
>  src/remote/remote_daemon.c    |   6 +--
>  src/rpc/virnetdaemon.c        | 109 ++++++++++++++++++++++++++++++++++++------
>  src/rpc/virnetdaemon.h        |   8 +++-
>  src/rpc/virnetserver.c        |   8 ++++
>  src/rpc/virnetserver.h        |   1 +
>  src/rpc/virnetserverservice.c |   1 -
>  src/util/vireventthread.c     |   1 +
>  src/util/virthreadpool.c      |  65 +++++++++++++++++--------
>  src/util/virthreadpool.h      |   6 +--
>  18 files changed, 267 insertions(+), 51 deletions(-)
>