Re: [Intel-wired-lan] [PATCH] net/i40e: Replace 0-length array with flexible array

Gustavo A. R. Silva
2023-01-06T16:28:02Z

On Thu, Jan 05, 2023 at 03:46:01PM -0800, Kees Cook wrote:
> Zero-length arrays are deprecated[1]. Replace struct i40e_lump_tracking's
> "list" 0-length array with a flexible array. Detected with GCC 13,
> using -fstrict-flex-arrays=3:
>
> In function 'i40e_put_lump',
> inlined from 'i40e_clear_interrupt_scheme' at drivers/net/ethernet/intel/i40e/i40e_main.c:5145:2:
> drivers/net/ethernet/intel/i40e/i40e_main.c:278:27: warning: array subscript <unknown> is outside array bounds of 'u16[0]' {aka 'short unsigned int[]'} [-Warray-bounds=]
> 278 | pile->list[i] = 0;
> | ~~~~~~~~~~^~~
> drivers/net/ethernet/intel/i40e/i40e.h: In function 'i40e_clear_interrupt_scheme':
> drivers/net/ethernet/intel/i40e/i40e.h:179:13: note: while referencing 'list'
> 179 | u16 list[0];
> | ^~~~
>
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays
>
> Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
> Cc: Tony Nguyen <anthony.l.nguyen@intel.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
> Cc: intel-wired-lan@lists.osuosl.org
> Cc: netdev@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks!
--
Gustavo

> ---
> drivers/net/ethernet/intel/i40e/i40e.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h
> index 60e351665c70..3a1c28ca5bb4 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e.h
> +++ b/drivers/net/ethernet/intel/i40e/i40e.h
> @@ -176,7 +176,7 @@ enum i40e_interrupt_policy {
>
> struct i40e_lump_tracking {
> u16 num_entries;
> - u16 list[0];
> + u16 list[];
> #define I40E_PILE_VALID_BIT 0x8000
> #define I40E_IWARP_IRQ_PILE_ID (I40E_PILE_VALID_BIT - 2)
> };
> --
> 2.34.1
>
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