diff options
author | Jason Wang <jasowang@redhat.com> | 2018-12-13 10:53:37 +0800 |
---|---|---|
committer | Ben Hutchings <ben@decadent.org.uk> | 2019-02-11 17:54:25 +0000 |
commit | 9b99c4b9160ee4fb323fb647aa079ad81411a706 (patch) | |
tree | 7057e26a945206eeeca31e243daa062b1241ebe2 | |
parent | eee77673af65ca33f2332abc2d4173ac25bedefd (diff) |
vhost: make sure used idx is seen before log in vhost_add_used_n()
commit 841df922417eb82c835e93d4b93eb6a68c99d599 upstream.
We miss a write barrier that guarantees used idx is updated and seen
before log. This will let userspace sync and copy used ring before
used idx is update. Fix this by adding a barrier before log_write().
Fixes: 8dd014adfea6f ("vhost-net: mergeable buffers support")
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
-rw-r--r-- | drivers/vhost/vhost.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index a9dfe6bd70eb..337e1d04871f 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1411,6 +1411,8 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads, return -EFAULT; } if (unlikely(vq->log_used)) { + /* Make sure used idx is seen before log. */ + smp_wmb(); /* Log used index update. */ log_write(vq->log_base, vq->log_addr + offsetof(struct vring_used, idx), |