Re: [PATCH net v2 1/2] net/mlx5: HWS, fix modify header pattern compare on big-endian

mlx5hws_pat_compare_pattern() casts each __be64 action to __be32 to
compare only its control dword. On big-endian this keeps the data dword
instead, which HWS clears from the pattern of set and add actions. Two
such actions writing the same value into different fields then share a
pattern and the second rule modifies the wrong field.

Read the first dword of each action from memory instead. Little-endian
behavior is unchanged.

Discovered by an AI code review agent [1] and confirmed by code
inspection. Not reproduced for lack of big-endian hardware running HWS.

Fixes: aefc15a0fa1c ("net/mlx5: HWS, added modify header pattern and args handling")
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20261010120147.135825-1-acassen%40corp.free.fr [1]
Signed-off-by: Alexandre Cassen <redacted>
---
  .../net/ethernet/mellanox/mlx5/core/steering/hws/pat_arg.c    | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/pat_arg.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/pat_arg.c
index 9af449c2b4d5..512299b59fd0 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/pat_arg.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/pat_arg.c

@@ -116,8 +116,8 @@ static bool mlx5hws_pat_compare_pattern(int cur_num_of_actions,
  				return false;
  		} else {
  			/* Compare just the control, not the values */
-			if ((__force __be32)actions[i] !=
-			    (__force __be32)cur_actions[i])
+			if (*(__be32 *)&actions[i] !=
+			    *(__be32 *)&cur_actions[i])
  				return false;
  		}
  	}