[PATCH 4.4 131/241] RDMA/cxgb4: Fix null pointer dereference on alloc_skb failure

From: Greg Kroah-Hartman
Date: Sun Jun 09 2019 - 13:05:58 EST

[ Upstream commit a6d2a5a92e67d151c98886babdc86d530d27111c ]

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

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@xxxxxxxxxxxxx>
Acked-by: Potnuri Bharat Teja <bharat@xxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/infiniband/hw/cxgb4/cm.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c
index c9cffced00ca1..54fd4d81a3f1f 100644
--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -360,6 +360,8 @@ static struct sk_buff *get_skb(struct sk_buff *skb, int len, gfp_t gfp)
} else {
skb = alloc_skb(len, gfp);
+ if (!skb)
+ return NULL;
t4_set_arp_err_handler(skb, NULL, NULL);
return skb;