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nixge: fix mac address error handling again 

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>
pull/78/merge
Arnd Bergmann 2021-11-22 16:02:49 +01:00 committed by David S. Miller
parent 7a61432dc8
commit a68229ca63
1 changed files with 2 additions and 2 deletions
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4
drivers/net/ethernet/ni/nixge.c
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@ -1209,7 +1209,7 @@ static void *nixge_get_nvmem_address(struct device *dev)
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);
@ -1282,7 +1282,7 @@ static int nixge_probe(struct platform_device *pdev)
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 {