From: Colin Ian King <colin.king@canonical.com>
Date: Sat, 13 Apr 2019 17:00:26 +0100
Subject: RDMA/cxgb4: Fix null pointer dereference on alloc_skb failure
Patch-mainline: v5.2-rc1
Git-commit: a6d2a5a92e67d151c98886babdc86d530d27111c
References: bsc#1136348 jsc#SLE-4684

Currently if alloc_skb fails to allocate the skb a null skb is passed to
t4_set_arp_err_handler and this ends up dereferencing the null skb.  Avoid
the NULL pointer dereference by checking for a NULL skb and returning
early.

Addresses-Coverity: ("Dereference null return")
Fixes: b38a0ad8ec11 ("RDMA/cxgb4: Set arp error handler for PASS_ACCEPT_RPL messages")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Potnuri Bharat Teja <bharat@chelsio.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/hw/cxgb4/cm.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -459,6 +459,8 @@ static struct sk_buff *get_skb(struct sk
 		skb_reset_transport_header(skb);
 	} else {
 		skb = alloc_skb(len, gfp);
+		if (!skb)
+			return NULL;
 	}
 	t4_set_arp_err_handler(skb, NULL, NULL);
 	return skb;