question about smatch error

[Roland Dreier]

Hi Dan,

I'm running smatch against some of my code, and I'm seeing the errors

drivers/infiniband/hw/mlx4/main.c +784 mlx4_addrconf_ifid_eui48(5) error: buffer overflow 'eui' 3 <= 3
drivers/infiniband/hw/mlx4/main.c +785 mlx4_addrconf_ifid_eui48(6) error: buffer overflow 'eui' 3 <= 4
drivers/infiniband/hw/mlx4/main.c +787 mlx4_addrconf_ifid_eui48(8) error: buffer overflow 'eui' 3 <= 3
drivers/infiniband/hw/mlx4/main.c +788 mlx4_addrconf_ifid_eui48(9) error: buffer overflow 'eui' 3 <= 4

and I can't understand what smatch is trying to say -- the code in
question is basically

	if (vlan_id < 0x1000) {
		eui[3] = vlan_id >> 8;
		eui[4] = vlan_id & 0xff;
	} else {
		eui[3] = 0xff;
		eui[4] = 0xfe;
	}

where eui is a u8*, and I don't see how smatch even thinks it knows how
big the buffer is in the first place.

This is with up-to-date smatch from git (my tree is at 798c4c13).

Thanks,
  Roland
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/