Re: [Qemu-devel] [PATCH v9 04/10] replay: fix processing async events

[Paolo Bonzini]

On 04/05/2017 10:41, Pavel Dovgalyuk wrote:
> From: Pavel Dovgalyuk <address@hidden>
> 
> Asynchronous events saved at checkpoints may invoke
> callbacks when processed. These callbacks may also generate/read
> new events (e.g. clock reads). Therefore event processing flag must be
> reset before callback invocation.
> 
> Signed-off-by: Pavel Dovgalyuk <address@hidden>
> ---
>  replay/replay-events.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/replay/replay-events.c b/replay/replay-events.c
> index 94a6dcccfc..768b505f3d 100644
> --- a/replay/replay-events.c
> +++ b/replay/replay-events.c
> @@ -295,13 +295,13 @@ void replay_read_events(int checkpoint)
>          if (!event) {
>              break;
>          }
> +        replay_finish_event();
> +        read_event_kind = -1;
>          replay_mutex_unlock();
>          replay_run_event(event);
>          replay_mutex_lock();
>  
>          g_free(event);
> -        replay_finish_event();
> -        read_event_kind = -1;

While at it, g_free can be moved outside the lock.

Also, replay_flush_events and replay_save_events are leaving the event
in events_list while releasing the lock, and only doing QTAILQ_REMOVE
after taking it back.  This can cause events to be processed twice.

I think it is worth fixing all of these.

Paolo

>      }
>  }
>  
>