From: Kees Cook kees@kernel.org
[ Upstream commit 4a6f18f28627e121bd1f74b5fcc9f945d6dbeb1e ]
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 kees@kernel.org Link: https://patch.msgid.link/20250210174504.work.075-kees@kernel.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@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 b330020dc0d67..f2bded847e61d 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 eb8169c03d899..0eb04d537038c 100644 --- a/include/linux/mlx4/device.h +++ b/include/linux/mlx4/device.h @@ -1116,7 +1116,7 @@ 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,