From: Arnd Bergmann arnd@arndb.de
commit a68229ca634066975fff6d4780155bd2eb14a82a upstream.
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: f3956ebb3bf0 ("ethernet: use eth_hw_addr_set() instead of ether_addr_copy()") Fixes: abcd3d6fc640 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/ni/nixge.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/net/ethernet/ni/nixge.c +++ b/drivers/net/ethernet/ni/nixge.c @@ -1211,7 +1211,7 @@ static void *nixge_get_nvmem_address(str
cell = nvmem_cell_get(dev, "address"); if (IS_ERR(cell)) - return NULL; + return cell;
mac = nvmem_cell_read(cell, &cell_size); nvmem_cell_put(cell); @@ -1284,7 +1284,7 @@ static int nixge_probe(struct platform_d ndev->max_mtu = NIXGE_JUMBO_MTU;
mac_addr = nixge_get_nvmem_address(&pdev->dev); - if (mac_addr && is_valid_ether_addr(mac_addr)) { + if (!IS_ERR(mac_addr) && is_valid_ether_addr(mac_addr)) { eth_hw_addr_set(ndev, mac_addr); kfree(mac_addr); } else {