[PATCH 22/22] IB/mlx4: fix sprintf format warning

[PATCH 22/22] IB/mlx4: fix sprintf format warning

[Arnd Bergmann]

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")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/infiniband/hw/mlx4/sysfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/mlx4/sysfs.c b/drivers/infiniband/hw/mlx4/sysfs.c
index 0ba5ba7540c8..e219093d2764 100644
--- 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;
-- 
2.9.0

Re: [PATCH 22/22] IB/mlx4: fix sprintf format warning

[Leon Romanovsky]

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On Fri, Jul 14, 2017 at 02:07:14PM +0200, Arnd Bergmann wrote:
> 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")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/infiniband/hw/mlx4/sysfs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>

Thanks,
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>

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