net: mvneta: fix possible use-after-free in mvneta_xdp_put_buff

Release first buffer as last one since it contains references
to subsequent fragments. This code will be optimized introducing
multi-buffer bit in xdp_buff structure.

Fixes: ca0e014609f05 ("net: mvneta: move skb build after descriptors processing")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index dfcb176..69a9000 100644 (file)
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -2029,11 +2029,11 @@ mvneta_xdp_put_buff(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
        struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
        int i;
 
-       page_pool_put_page(rxq->page_pool, virt_to_head_page(xdp->data),
-                          sync_len, napi);
        for (i = 0; i < sinfo->nr_frags; i++)
                page_pool_put_full_page(rxq->page_pool,
                                        skb_frag_page(&sinfo->frags[i]), napi);
+       page_pool_put_page(rxq->page_pool, virt_to_head_page(xdp->data),
+                          sync_len, napi);
 }
 
 static int