* [PATCH] [v2] nixge: fix mac address error handling again
@ 2021-11-22 15:07 Arnd Bergmann
0 siblings, 0 replies; only message in thread
From: Arnd Bergmann @ 2021-11-22 15:07 UTC (permalink / raw)
To: David S. Miller, Jakub Kicinski, Moritz Fischer
Cc: Arnd Bergmann, Yang Yingliang, Huazhong Tan, Yufeng Mo,
Cai Huoqing, netdev, linux-kernel
From: Arnd Bergmann <arnd@arndb.de>
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 NULL on error for consistency,
this addresses the bug and the compiler warning.
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>
---
v2: return NULL consistently, rather than returning error pointer
---
drivers/net/ethernet/ni/nixge.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/net/ethernet/ni/nixge.c b/drivers/net/ethernet/ni/nixge.c
index cfeb7620ae20..9d8826ad84a6 100644
--- a/drivers/net/ethernet/ni/nixge.c
+++ b/drivers/net/ethernet/ni/nixge.c
@@ -1213,6 +1213,8 @@ static void *nixge_get_nvmem_address(struct device *dev)
mac = nvmem_cell_read(cell, &cell_size);
nvmem_cell_put(cell);
+ if (IS_ERR(mac))
+ return NULL;
return mac;
}
--
2.29.2
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