linux-kernel - [PATCH AUTOSEL 4.14 056/371] RDMA/iw_cxgb4: Fix the unchecked ep dereference

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Date:   Thu, 16 Jan 2020 12:12:04 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Raju Rangoju <rajur@...lsio.com>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        Jason Gunthorpe <jgg@...lanox.com>,
        Sasha Levin <sashal@...nel.org>, linux-rdma@...r.kernel.org
Subject: [PATCH AUTOSEL 4.14 056/371] RDMA/iw_cxgb4: Fix the unchecked ep dereference

From: Raju Rangoju <rajur@...lsio.com>

[ Upstream commit 3352976c892301fd576a2e9ff0ac7337b2e2ca48 ]

The patch 944661dd97f4: "RDMA/iw_cxgb4: atomically lookup ep and get a
reference" from May 6, 2016, leads to the following Smatch complaint:

    drivers/infiniband/hw/cxgb4/cm.c:2953 terminate()
    error: we previously assumed 'ep' could be null (see line 2945)

Fixes: 944661dd97f4 ("RDMA/iw_cxgb4: atomically lookup ep and get a reference")
Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Raju Rangoju <rajur@...lsio.com>
Signed-off-by: Jason Gunthorpe <jgg@...lanox.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/infiniband/hw/cxgb4/cm.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c
index bb36cdf82a8d..3668cc71b47e 100644
--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -2923,15 +2923,18 @@ static int terminate(struct c4iw_dev *dev, struct sk_buff *skb)
 	ep = get_ep_from_tid(dev, tid);
 	BUG_ON(!ep);
 
-	if (ep && ep->com.qp) {
-		pr_warn("TERM received tid %u qpid %u\n",
-			tid, ep->com.qp->wq.sq.qid);
-		attrs.next_state = C4IW_QP_STATE_TERMINATE;
-		c4iw_modify_qp(ep->com.qp->rhp, ep->com.qp,
-			       C4IW_QP_ATTR_NEXT_STATE, &attrs, 1);
+	if (ep) {
+		if (ep->com.qp) {
+			pr_warn("TERM received tid %u qpid %u\n", tid,
+				ep->com.qp->wq.sq.qid);
+			attrs.next_state = C4IW_QP_STATE_TERMINATE;
+			c4iw_modify_qp(ep->com.qp->rhp, ep->com.qp,
+				       C4IW_QP_ATTR_NEXT_STATE, &attrs, 1);
+		}
+
+		c4iw_put_ep(&ep->com);
 	} else
 		pr_warn("TERM received tid %u no ep/qp\n", tid);
-	c4iw_put_ep(&ep->com);
 
 	return 0;
 }
-- 
2.20.1