The change to eth_hw_addr_set() caused gcc to correctly spot a
bug that was introduced in an earlier incorrect fix:
In file included from include/linux/etherdevice.h:21,
from drivers/net/ethernet/ni/nixge.c:7:
In function '__dev_addr_set',
inlined from 'eth_hw_addr_set' at include/linux/etherdevice.h:319:2,
inlined from 'nixge_probe' at drivers/net/ethernet/ni/nixge.c:1286:3:
include/linux/netdevice.h:4648:9: error: 'memcpy' reading 6 bytes from a region of size 0 [-Werror=stringop-overread]
4648 | memcpy(dev->dev_addr, addr, len);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
As nixge_get_nvmem_address() can return either NULL or an error
pointer, the NULL check is wrong, and we can end up reading from
ERR_PTR(-EOPNOTSUPP), which gcc knows to contain zero readable
bytes.
Make the function always return an error pointer again but fix
the check to match that.
Fixes: f3956ebb3b ("ethernet: use eth_hw_addr_set() instead of ether_addr_copy()")
Fixes: abcd3d6fc6 ("net: nixge: Fix error path for obtaining mac address")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
a68229ca63