[PATCH] net/i40e: Replace 0-length array with flexible array

Kees Cook
2023-01-05T23:46:09Z

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>
---
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