[PATCH v2 1/3] vhost: fix error path in vhost_init_used()
From: Greg Kurz <hidden>
Date: 2016-02-16 14:54:41
Also in:
kvm, lkml
Subsystem:
the rest, virtio host (vhost) · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
We don't want side effects. If something fails, we rollback vq->is_le to its previous value. Signed-off-by: Greg Kurz <redacted> --- drivers/vhost/vhost.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index ad2146a9ab2d..236553e81027 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c@@ -1156,6 +1156,8 @@ int vhost_init_used(struct vhost_virtqueue *vq) { __virtio16 last_used_idx; int r; + bool is_le = vq->is_le; + if (!vq->private_data) { vq->is_le = virtio_legacy_is_little_endian(); return 0;
@@ -1165,15 +1167,20 @@ int vhost_init_used(struct vhost_virtqueue *vq) r = vhost_update_used_flags(vq); if (r) - return r; + goto err; vq->signalled_used_valid = false; - if (!access_ok(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx)) - return -EFAULT; + if (!access_ok(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx)) { + r = -EFAULT; + goto err; + } r = __get_user(last_used_idx, &vq->used->idx); if (r) - return r; + goto err; vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx); return 0; +err: + vq->is_le = is_le; + return r; } EXPORT_SYMBOL_GPL(vhost_init_used);