[PATCH V5 8/9] vhost: correctly set dirty pages in MMU notifiers callback

Jason Wang
2019-08-09T05:49:45Z

We need make sure there's no reference on the map before trying to
mark set dirty pages.

Reported-by: Michael S. Tsirkin <mst@redhat.com>
Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address")
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/vhost.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 29e8abe694f7..d8863aaaf0f6 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -386,13 +386,12 @@ static void vhost_invalidate_vq_start(struct vhost_virtqueue *vq,
++vq->invalidate_count;

map = vq->maps[index];
- if (map) {
+ if (map)
vq->maps[index] = NULL;
- vhost_set_map_dirty(vq, map, index);
- }
spin_unlock(&vq->mmu_lock);

if (map) {
+ vhost_set_map_dirty(vq, map, index);
vhost_map_unprefetch(map);
}
}
--
2.18.1