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net/mlx4_core: Avoid impossible mlx4_db_alloc() order value

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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>
This commit is contained in:
Kees Cook 2025-02-10 09:45:05 -08:00 • committed by Jakub Kicinski
parent 0025fa4525
commit 4a6f18f286
2 changed files with 4 additions and 4 deletions
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6
drivers/net/ethernet/mellanox/mlx4/alloc.c
View file

@ -660,9 +660,9 @@ 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) {
@ -690,7 +690,7 @@ found:
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;

2
include/linux/mlx4/device.h
View file

@ -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,