[PATCH 6.1 0936/1146] net: fec: check the return value of build_skb()

Greg Kroah-Hartman
2022-12-28T16:44:14Z

From: Wei Fang <wei.fang@nxp.com>

[ Upstream commit 19e72b064fc32cd58f6fc0b1eb64ac2e4f770e76 ]

The build_skb might return a null pointer but there is no check on the
return value in the fec_enet_rx_queue(). So a null pointer dereference
might occur. To avoid this, we check the return value of build_skb. If
the return value is a null pointer, the driver will recycle the page and
update the statistic of ndev. Then jump to rx_processing_done to clear
the status flags of the BD so that the hardware can recycle the BD.

Fixes: 95698ff6177b ("net: fec: using page pool to manage RX buffers")
Signed-off-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Shenwei Wang <Shenwei.wang@nxp.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Link: https://lore.kernel.org/r/20221219022755.1047573-1-wei.fang@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/freescale/fec_main.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 23e1a94b9ce4..f250b0df27fb 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -1642,6 +1642,14 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id)
* bridging applications.
*/
skb = build_skb(page_address(page), PAGE_SIZE);
+ if (unlikely(!skb)) {
+ page_pool_recycle_direct(rxq->page_pool, page);
+ ndev->stats.rx_dropped++;
+
+ netdev_err_once(ndev, "build_skb failed!\n");
+ goto rx_processing_done;
+ }
+
skb_reserve(skb, FEC_ENET_XDP_HEADROOM);
skb_put(skb, pkt_len - 4);
skb_mark_for_recycle(skb);
--
2.35.1