[PATCH 3.16 205/305] net/mlx4: Fix UBSAN warning of signed integer overflow

[Ben Hutchings]

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

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

From: Aya Levin <ayal@xxxxxxxxxxxx>

commit a463146e67c848cbab5ce706d6528281b7cded08 upstream.

UBSAN: Undefined behavior in
drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:626:29
signed integer overflow: 1802201963 + 1802201963 cannot be represented
in type 'int'

The union of res_reserved and res_port_rsvd[MLX4_MAX_PORTS] monitors
granting of reserved resources. The grant operation is calculated and
protected, thus both members of the union cannot be negative.  Changed
type of res_reserved and of res_port_rsvd[MLX4_MAX_PORTS] from signed
int to unsigned int, allowing large value.

Fixes: 5a0d0a6161ae ("mlx4: Structures and init/teardown for VF resource quotas")
Signed-off-by: Aya Levin <ayal@xxxxxxxxxxxx>
Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx4/mlx4.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx4/mlx4.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4.h
@@ -518,8 +518,8 @@ struct slave_list {
 struct resource_allocator {
 	spinlock_t alloc_lock; /* protect quotas */
 	union {
-		int res_reserved;
-		int res_port_rsvd[MLX4_MAX_PORTS];
+		unsigned int res_reserved;
+		unsigned int res_port_rsvd[MLX4_MAX_PORTS];
 	};
 	union {
 		int res_free;