[PATCH v2 4/7] vhost: fix check on virtqueue access in async registration

[Maxime Coquelin]

Acquiring the access lock is not enough to ensure
virtqueue's metadata such as vring pointers are valid.

The access status must also be checked.

Fixes: 78639d54563a ("vhost: introduce async enqueue registration API")
Cc: sta...@dpdk.org

Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
---
 lib/vhost/vhost.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index 5428ff4a25..ccd3c0e865 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -1857,7 +1857,15 @@ rte_vhost_async_channel_register(int vid, uint16_t 
queue_id)
                return -1;
 
        rte_rwlock_write_lock(&vq->access_lock);
+
+       if (unlikely(!vq->access_ok)) {
+               ret = -1;
+               goto out_unlock;
+       }
+
        ret = async_channel_register(dev, vq);
+
+out_unlock:
        rte_rwlock_write_unlock(&vq->access_lock);
 
        return ret;
@@ -1909,6 +1917,11 @@ rte_vhost_async_channel_unregister(int vid, uint16_t 
queue_id)
                return ret;
        }
 
+       if (unlikely(!vq->access_ok)) {
+               ret = -1;
+               goto out_unlock;
+       }
+
        if (!vq->async) {
                ret = 0;
        } else if (vq->async->pkts_inflight_n) {
@@ -1920,6 +1933,7 @@ rte_vhost_async_channel_unregister(int vid, uint16_t 
queue_id)
                ret = 0;
        }
 
+out_unlock:
        rte_rwlock_write_unlock(&vq->access_lock);
 
        return ret;
-- 
2.41.0