GCC can see that the value range for "order" is capped, but this leads
it to consider that it might be negative, leading to a false positive
warning (with GCC 15 with -Warray-bounds -fdiagnostics-details):
../drivers/net/ethernet/mellanox/mlx4/alloc.c:691:47: error: array subscript -1
is below array bounds of 'long unsigned int *[2]' [-Werror=array-bounds=]
691 | i = find_first_bit(pgdir->bits[o], MLX4_DB_PER_PAGE >>
o);
| ~~~~~~~~~~~^~~
'mlx4_alloc_db_from_pgdir': events 1-2
691 | i = find_first_bit(pgdir->bits[o], MLX4_DB_PER_PAGE >>
o); |
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| | |
| | (2)
out of array bounds here
| (1) when the condition is evaluated to true
In file included from
../drivers/net/ethernet/mellanox/mlx4/mlx4.h:53,
from ../drivers/net/ethernet/mellanox/mlx4/alloc.c:42:
../include/linux/mlx4/device.h:664:33: note: while referencing 'bits'
664 | unsigned long *bits[2];
| ^~~~
Switch the argument to unsigned int, which removes the compiler needing
to consider negative values.
Signed-off-by: Kees Cook <k...@kernel.org>
---
Cc: Tariq Toukan <tar...@nvidia.com>
Cc: Andrew Lunn <andrew+net...@lunn.ch>
Cc: "David S. Miller" <da...@davemloft.net>
Cc: Eric Dumazet <eduma...@google.com>
Cc: Jakub Kicinski <k...@kernel.org>
Cc: Paolo Abeni <pab...@redhat.com>
Cc: Yishai Hadas <yish...@nvidia.com>
Cc: net...@vger.kernel.org
Cc: linux-r...@vger.kernel.org
---
drivers/net/ethernet/mellanox/mlx4/alloc.c | 6 +++---
include/linux/mlx4/device.h | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/alloc.c
b/drivers/net/ethernet/mellanox/mlx4/alloc.c
index b330020dc0d6..f2bded847e61 100644
--- a/drivers/net/ethernet/mellanox/mlx4/alloc.c
+++ b/drivers/net/ethernet/mellanox/mlx4/alloc.c
@@ -682,9 +682,9 @@ static struct mlx4_db_pgdir *mlx4_alloc_db_pgdir(struct
device *dma_device)
}
static int mlx4_alloc_db_from_pgdir(struct mlx4_db_pgdir *pgdir,
- struct mlx4_db *db, int order)
+ struct mlx4_db *db, unsigned int order)
{
- int o;
+ unsigned int o;
int i;
for (o = order; o <= 1; ++o) {
@@ -712,7 +712,7 @@ static int mlx4_alloc_db_from_pgdir(struct mlx4_db_pgdir
*pgdir,
return 0;
}
-int mlx4_db_alloc(struct mlx4_dev *dev, struct mlx4_db *db, int order)
+int mlx4_db_alloc(struct mlx4_dev *dev, struct mlx4_db *db, unsigned int order)
{
struct mlx4_priv *priv = mlx4_priv(dev);
struct mlx4_db_pgdir *pgdir;
diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
index 27f42f713c89..86f0f2a25a3d 100644
--- a/include/linux/mlx4/device.h
+++ b/include/linux/mlx4/device.h
@@ -1135,7 +1135,7 @@ int mlx4_write_mtt(struct mlx4_dev *dev, struct mlx4_mtt
*mtt,
int mlx4_buf_write_mtt(struct mlx4_dev *dev, struct mlx4_mtt *mtt,
struct mlx4_buf *buf);
-int mlx4_db_alloc(struct mlx4_dev *dev, struct mlx4_db *db, int order);
+int mlx4_db_alloc(struct mlx4_dev *dev, struct mlx4_db *db, unsigned int
order);
void mlx4_db_free(struct mlx4_dev *dev, struct mlx4_db *db);
int mlx4_alloc_hwq_res(struct mlx4_dev *dev, struct mlx4_hwq_resources *wqres,
--
2.34.1
