Re: [PATCH 1/7] vhost_user: Reset vq enable flag in vu_cleanup()

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Jul 31, 2026 at 06:46:22PM +0200, Laurent Vivier wrote:
> vu_cleanup() resets most virtqueue state (started, notification,
> file descriptors) but does not reset the enable flag.  After a
> QEMU disconnect and reconnect, the stale enable flag causes
> vu_set_vring_enable_exec() to hit its early return check
> (vq->enable == enable), skipping the threading_start_thread() call
> and leaving the worker thread stopped.
> 
> Reset vq->enable to false in vu_cleanup() alongside the other
> virtqueue state.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

AFAICT it would make sense to apply this fix immediately, independent
of the rest of the series.

> ---
>  vhost_user.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/vhost_user.c b/vhost_user.c
> index 9e382c21f963..8ba3949e4e9d 100644
> --- a/vhost_user.c
> +++ b/vhost_user.c
> @@ -1083,6 +1083,7 @@ void vu_cleanup(struct vu_dev *vdev)
>  		struct vu_virtq *vq = &vdev->vq[i];
>  
>  		vq->started = false;
> +		vq->enable = false;
>  		vq->notification = true;
>  
>  		if (vq->call_fd != -1) {
> -- 
> 2.54.0
> 

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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