4.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang <jasowang@xxxxxxxxxx> [ Upstream commit b8f1f65882f07913157c44673af7ec0b308d03eb ] Sock will be NULL if we pass -1 to vhost_net_set_backend(), but when we meet errors during ubuf allocation, the code does not check for NULL before calling sockfd_put(), this will lead NULL dereferencing. Fixing by checking sock pointer before. Fixes: bab632d69ee4 ("vhost: vhost TX zero-copy support") Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/vhost/net.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -1219,7 +1219,8 @@ err_used: if (ubufs) vhost_net_ubuf_put_wait_and_free(ubufs); err_ubufs: - sockfd_put(sock); + if (sock) + sockfd_put(sock); err_vq: mutex_unlock(&vq->mutex); err: