IB/mlx4: fix sprintf format warning

gcc-7 points out that a negative port_num value would overflow the
string buffer:

  drivers/infiniband/hw/mlx4/sysfs.c: In function 'mlx4_ib_device_register_sysfs':
  drivers/infiniband/hw/mlx4/sysfs.c:251:16: error: 'sprintf' may write a terminating nul past the end of the destination [-Werror=format-overflow=]
  drivers/infiniband/hw/mlx4/sysfs.c:251:2: note: 'sprintf' output between 2 and 11 bytes into a destination of size 10
  drivers/infiniband/hw/mlx4/sysfs.c:303:17: error: 'sprintf' may write a terminating nul past the end of the destination [-Werror=format-overflow=]
  drivers/infiniband/hw/mlx4/sysfs.c:303:3: note: 'sprintf' output between 2 and 11 bytes into a destination of size 10

While we should be able to assume that port_num is positive here, making
the buffer one byte longer has no downsides and avoids the warning.

Fixes: c1e7e466120b ("IB/mlx4: Add iov directory in sysfs under the ib device")
Link: http://lkml.kernel.org/r/20170714120720.906842-23-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/infiniband/hw/mlx4/sysfs.c b/drivers/infiniband/hw/mlx4/sysfs.c
index 0ba5ba7540c87e32bbcf795a7b581f1b4b7a49aa..e219093d2764536a58c7c362a08167361ed0e93a 100644 (file)
--- a/drivers/infiniband/hw/mlx4/sysfs.c
+++ b/drivers/infiniband/hw/mlx4/sysfs.c
@@ -221,7 +221,7 @@ void del_sysfs_port_mcg_attr(struct mlx4_ib_dev *device, int port_num,
 static int add_port_entries(struct mlx4_ib_dev *device, int port_num)
 {
        int i;
-       char buff[10];
+       char buff[11];
        struct mlx4_ib_iov_port *port = NULL;
        int ret = 0 ;
        struct ib_port_attr attr;