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: ca0e014 ("net: mvneta: move skb build after descriptors processing")
Signed-off-by: Lorenzo Bianconi <[email protected]>
Acked-by: Jesper Dangaard Brouer <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: LorenzoBianconi

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