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| author | Jason Wang <jasowang@redhat.com> | 2018-12-13 10:53:37 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-09 17:14:45 +0100 |
| commit | 2510d91bdafe6ebe95864290866bb6c3e714b6e8 (patch) | |
| tree | 39237129ba64774811a03e62372b8b661991e568 | |
| parent | 3009452fb260459deff51533f284dd0d004cbbac (diff) | |
| download | linux-stable-2510d91bdafe6ebe95864290866bb6c3e714b6e8.tar.gz linux-stable-2510d91bdafe6ebe95864290866bb6c3e714b6e8.tar.bz2 linux-stable-2510d91bdafe6ebe95864290866bb6c3e714b6e8.zip | |
vhost: make sure used idx is seen before log in vhost_add_used_n()
[ Upstream commit 841df922417eb82c835e93d4b93eb6a68c99d599 ]
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 ffdd4e937d1d..97518685ab58 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -2231,6 +2231,8 @@ 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), |