[PATCH 4.2.y-ckt 263/273] net/mlx4_core: Fix potential corruption in counters database

[Kamal Mostafa]

4.2.8-ckt5 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Eran Ben Elisha <eranbe@xxxxxxxxxxxx>

commit 6b94bab0ee8d5def6a2aac0ef6204ee6e24386b6 upstream.

The error flow in procedure handle_existing_counter() is wrong.

The procedure should exit after encountering the error, not continue
as if everything is OK.

Fixes: 68230242cdbc ('net/mlx4_core: Add port attribute when tracking counters')
Signed-off-by: Eran Ben Elisha <eranbe@xxxxxxxxxxxx>
Signed-off-by: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx4/resource_tracker.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
index 8bead97..b2614a8 100644
--- a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
+++ b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
@@ -905,11 +905,13 @@ static int handle_existing_counter(struct mlx4_dev *dev, u8 slave, int port,
 
 	spin_lock_irq(mlx4_tlock(dev));
 	r = find_res(dev, counter_index, RES_COUNTER);
-	if (!r || r->owner != slave)
+	if (!r || r->owner != slave) {
 		ret = -EINVAL;
-	counter = container_of(r, struct res_counter, com);
-	if (!counter->port)
-		counter->port = port;
+	} else {
+		counter = container_of(r, struct res_counter, com);
+		if (!counter->port)
+			counter->port = port;
+	}
 
 	spin_unlock_irq(mlx4_tlock(dev));
 	return ret;
-- 
2.7.0