From: Arnd Bergmann <arnd@xxxxxxxx>
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@xxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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 {
