[PATCH 4.19 34/49] IB/isert: Fix possible list corruption in CMA handler

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Saravanan Vajravel <saravanan.vajravel@broadcom.com>

[ Upstream commit 7651e2d6c5b359a28c2d4c904fec6608d1021ca8 ]

When ib_isert module receives connection error event, it is
releasing the isert session and removes corresponding list
node but it doesn't take appropriate mutex lock to remove
the list node.  This can lead to linked  list corruption

Fixes: bd3792205aae ("iser-target: Fix pending connections handling in target stack shutdown sequnce")
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Saravanan Vajravel <saravanan.vajravel@broadcom.com>
Link: https://lore.kernel.org/r/20230606102531.162967-3-saravanan.vajravel@broadcom.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/infiniband/ulp/isert/ib_isert.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 51e4f4e112841..60594dad55455 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -742,9 +742,13 @@ static int
 isert_connect_error(struct rdma_cm_id *cma_id)
 {
 	struct isert_conn *isert_conn = cma_id->qp->qp_context;
+	struct isert_np *isert_np = cma_id->context;
 
 	ib_drain_qp(isert_conn->qp);
+
+	mutex_lock(&isert_np->mutex);
 	list_del_init(&isert_conn->node);
+	mutex_unlock(&isert_np->mutex);
 	isert_conn->cm_id = NULL;
 	isert_put_conn(isert_conn);
 
-- 
2.39.2