[PATCH 3.16 105/370] IB/mlx4: Fix out-of-range array index in destroy qp flow

[Ben Hutchings]

3.16.42-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx>

commit c482af646d0809a8d5e1b7f4398cce3592589b98 upstream.

For non-special QPs, the port value becomes non-zero only at the
RESET-to-INIT transition. If the QP has not undergone that transition,
its port number value is still zero.

If such a QP is destroyed before being moved out of the RESET state,
subtracting one from the qp port number results in a negative value.
Using that negative value as an index into the qp1_proxy array
results in an out-of-bounds array reference.

Fix this by testing that the QP type is one that uses qp1_proxy before
using the port number. For special QPs of all types, the port number is
specified at QP creation time.

Fixes: 9433c188915c ("IB/mlx4: Invoke UPDATE_QP for proxy QP1 on MAC changes")
Signed-off-by: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/infiniband/hw/mlx4/qp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/hw/mlx4/qp.c
+++ b/drivers/infiniband/hw/mlx4/qp.c
@@ -1153,7 +1153,8 @@ int mlx4_ib_destroy_qp(struct ib_qp *qp)
 	if (is_qp0(dev, mqp))
 		mlx4_CLOSE_PORT(dev->dev, mqp->port);
 
-	if (dev->qp1_proxy[mqp->port - 1] == mqp) {
+	if (mqp->mlx4_ib_qp_type == MLX4_IB_QPT_PROXY_GSI &&
+	    dev->qp1_proxy[mqp->port - 1] == mqp) {
 		mutex_lock(&dev->qp1_proxy_lock[mqp->port - 1]);
 		dev->qp1_proxy[mqp->port - 1] = NULL;
 		mutex_unlock(&dev->qp1_proxy_lock[mqp->port - 1]);