The benet driver copies both fw_ver (32 bytes) and fw_on_flash (32 bytes)
into ethtool_drvinfo->fw_version (32 bytes), leading to a potential
string truncation warning when built with W=1.

Store fw_on_flash in ethtool_drvinfo->erom_version instead, which some
drivers use to report secondary firmware information.

Signed-off-by: Ankan Biswas <spyjetfayed@gmail.com>
---
 drivers/net/ethernet/emulex/benet/be_ethtool.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/emulex/benet/be_ethtool.c b/drivers/net/ethernet/emulex/benet/be_ethtool.c
index f9216326bdfe..752f838f1abf 100644
--- a/drivers/net/ethernet/emulex/benet/be_ethtool.c
+++ b/drivers/net/ethernet/emulex/benet/be_ethtool.c
@@ -221,12 +221,20 @@ static void be_get_drvinfo(struct net_device *netdev,
 	struct be_adapter *adapter = netdev_priv(netdev);
 
 	strscpy(drvinfo->driver, DRV_NAME, sizeof(drvinfo->driver));
-	if (!memcmp(adapter->fw_ver, adapter->fw_on_flash, FW_VER_LEN))
+	if (!memcmp(adapter->fw_ver, adapter->fw_on_flash, FW_VER_LEN)) {
 		strscpy(drvinfo->fw_version, adapter->fw_ver,
 			sizeof(drvinfo->fw_version));
-	else
-		snprintf(drvinfo->fw_version, sizeof(drvinfo->fw_version),
-			 "%s [%s]", adapter->fw_ver, adapter->fw_on_flash);
+
+	} else {
+		strscpy(drvinfo->fw_version, adapter->fw_ver,
+			sizeof(drvinfo->fw_version));
+
+		/*
+		 * Report fw_on_flash in ethtool's erom_version field.
+		 */
+		strscpy(drvinfo->erom_version, adapter->fw_on_flash,
+			sizeof(drvinfo->erom_version));
+	}
 
 	strscpy(drvinfo->bus_info, pci_name(adapter->pdev),
 		sizeof(drvinfo->bus_info));
-- 
2.51.1

On Fri, 24 Oct 2025 23:45:41 +0530 Ankan Biswas wrote:
> The benet driver copies both fw_ver (32 bytes) and fw_on_flash (32 bytes)
> into ethtool_drvinfo->fw_version (32 bytes), leading to a potential
> string truncation warning when built with W=1.
> 
> Store fw_on_flash in ethtool_drvinfo->erom_version instead, which some
> drivers use to report secondary firmware information.

You are changing user-visible behavior to silence a W=1 warning.
I can't stress enough how bad of an idea this is.
Please find a better fix.. or leave this code be.

On 10/29/25 7:12 AM, Jakub Kicinski wrote:
> On Fri, 24 Oct 2025 23:45:41 +0530 Ankan Biswas wrote:
>> The benet driver copies both fw_ver (32 bytes) and fw_on_flash (32 bytes)
>> into ethtool_drvinfo->fw_version (32 bytes), leading to a potential
>> string truncation warning when built with W=1.
>>
>> Store fw_on_flash in ethtool_drvinfo->erom_version instead, which some
>> drivers use to report secondary firmware information.
> 
> You are changing user-visible behavior to silence a W=1 warning.
> I can't stress enough how bad of an idea this is.
> Please find a better fix.. or leave this code be.

Hi Jakub,

Thanks for the feedback. I felt this would be better than the value 
appearing truncated to the user. However, yes this is not the ideal fix. 
Will avoid modifying user-visible behavior.

An ideal fix may require a lot more changes, which may not be worth the 
effort at this point, so I guess it is better to drop this patch.


Best Regards,
Ankan Biswas