@@ -627,6 +627,9 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
int ret;
llnode = llist_del_all(&svq->completion_list);
+
+ mutex_lock(&svq->vq.mutex);
+
llist_for_each_entry_safe(cmd, t, llnode, tvc_completion_list) {
se_cmd = &cmd->tvc_se_cmd;
@@ -660,6 +663,8 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
vhost_scsi_release_cmd_res(se_cmd);
}
+ mutex_unlock(&svq->vq.mutex);
+
if (signal)
vhost_signal(&svq->vs->dev, &svq->vq);
}
@@ -1432,8 +1437,11 @@ static void vhost_scsi_tmf_resp_work(struct vhost_work *work)
else
resp_code = VIRTIO_SCSI_S_FUNCTION_REJECTED;
+ mutex_lock(&tmf->svq->vq.mutex);
vhost_scsi_send_tmf_resp(tmf->vhost, &tmf->svq->vq, tmf->in_iovs,
tmf->vq_desc, &tmf->resp_iov, resp_code);
+ mutex_unlock(&tmf->svq->vq.mutex);
+
vhost_scsi_release_tmf_res(tmf);
}
The vhost-scsi completion path may access vq->log_base when vq->log_used is already set to false. vhost-thread QEMU-thread vhost_scsi_complete_cmd_work() -> vhost_add_used() -> vhost_add_used_n() if (unlikely(vq->log_used)) QEMU disables vq->log_used via VHOST_SET_VRING_ADDR. mutex_lock(&vq->mutex); vq->log_used = false now! mutex_unlock(&vq->mutex); QEMU gfree(vq->log_base) log_used() -> log_write(vq->log_base) Assuming the VMM is QEMU. The vq->log_base is from QEMU userpace and can be reclaimed via gfree(). As a result, this causes invalid memory writes to QEMU userspace. The control queue path has the same issue. Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Acked-by: Jason Wang <jasowang@redhat.com> Reviewed-by: Mike Christie <michael.christie@oracle.com> --- Changed since v1: - Move lock to the begin and end of vhost_scsi_complete_cmd_work() as it is per-vq now. This reduces the number of mutex_lock(). - Move this bugfix patch to before dirty log tracking patches. drivers/vhost/scsi.c | 8 ++++++++ 1 file changed, 8 insertions(+)