From 21e27ac82db637d2f48f07b3777aae8e7ca52613 Mon Sep 17 00:00:00 2001
From: Bob Pearson <rpearsonhpe@gmail.com>
Date: Thu, 4 Mar 2021 13:20:49 -0600
Subject: [PATCH] RDMA/rxe: Fix missed IB reference counting in loopback

When the noted patch below extending the reference taken by
rxe_get_dev_from_net() in rxe_udp_encap_recv() until each skb is freed it
was not matched by a reference in the loopback path resulting in
underflows.

Fixes: 899aba891cab ("RDMA/rxe: Fix FIXME in rxe_udp_encap_recv()")
Link: https://lore.kernel.org/r/20210304192048.2958-1-rpearson@hpe.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/infiniband/sw/rxe/rxe_net.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
index 0701bd1ffd1a8..01662727dca08 100644
--- a/drivers/infiniband/sw/rxe/rxe_net.c
+++ b/drivers/infiniband/sw/rxe/rxe_net.c
@@ -407,14 +407,22 @@ int rxe_send(struct rxe_pkt_info *pkt, struct sk_buff *skb)
 	return 0;
 }
 
+/* fix up a send packet to match the packets
+ * received from UDP before looping them back
+ */
 void rxe_loopback(struct sk_buff *skb)
 {
+	struct rxe_pkt_info *pkt = SKB_TO_PKT(skb);
+
 	if (skb->protocol == htons(ETH_P_IP))
 		skb_pull(skb, sizeof(struct iphdr));
 	else
 		skb_pull(skb, sizeof(struct ipv6hdr));
 
-	rxe_rcv(skb);
+	if (WARN_ON(!ib_device_try_get(&pkt->rxe->ib_dev)))
+		kfree_skb(skb);
+	else
+		rxe_rcv(skb);
 }
 
 struct sk_buff *rxe_init_packet(struct rxe_dev *rxe, struct rxe_av *av,
-- 
GitLab