Re: [Qemu-devel] [PATCH] iothread: Make iothread_stop() idempotent

[Christian Borntraeger <borntraeger@de.ibm.com>]

On 09/26/2017 03:00 PM, Eduardo Habkost wrote:
> Currently, iothread_stop_all() makes all iothread objects unsafe
> to be destroyed, because qemu_thread_join() ends up being called
> twice.
> 
> To fix this, make iothread_stop() idempotent by checking
> thread->stopped.
> 
> Fixes the following crash:
> 
>   qemu-system-x86_64 -object iothread,id=iothread0 -monitor stdio -display none
>   QEMU 2.10.50 monitor - type 'help' for more information
>   (qemu) quit
>   qemu: qemu_thread_join: No such process
>   Aborted (core dumped)
> 
> Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>

> ---
>  iothread.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/iothread.c b/iothread.c
> index 44c8944dc4..59d0850988 100644
> --- a/iothread.c
> +++ b/iothread.c
> @@ -85,7 +85,7 @@ static int iothread_stop(Object *object, void *opaque)
>      IOThread *iothread;
> 
>      iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD);
> -    if (!iothread || !iothread->ctx) {
> +    if (!iothread || !iothread->ctx || iothread->stopping) {
>          return 0;
>      }
>      iothread->stopping = true;
>