[PATCH net] net: rnpgbe: Pass an expression directly in rnpgbe_rm_adapter()

[PATCH net] net: rnpgbe: Pass an expression directly in rnpgbe_rm_adapter()

[Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sun, 12 Jul 2026 20:25:10 +0200

The address of a data structure member was determined before
a corresponding null pointer check in the implementation of
the function “rnpgbe_rm_adapter”.

Thus avoid the risk for undefined behaviour by omitting the variable “hw”.
Pass the required address directly to a function call.

This issue was detected by using the Coccinelle software.

Fixes: 2ee95ec17e97c58b65e978a08b75fa8cb6424e4e ("net: rnpgbe: Add register_netdev")
Cc: stable@vger.kernel.org
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 drivers/net/ethernet/mucse/rnpgbe/rnpgbe_main.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_main.c b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_main.c
index 70a2b0082ba8..93cf757c951c 100644
--- a/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_main.c
+++ b/drivers/net/ethernet/mucse/rnpgbe/rnpgbe_main.c
@@ -245,7 +245,6 @@ static int rnpgbe_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 static void rnpgbe_rm_adapter(struct pci_dev *pdev)
 {
 	struct mucse *mucse = pci_get_drvdata(pdev);
-	struct mucse_hw *hw = &mucse->hw;
 	struct net_device *netdev;
 	int err;
 
@@ -253,7 +252,7 @@ static void rnpgbe_rm_adapter(struct pci_dev *pdev)
 		return;
 	netdev = mucse->netdev;
 	unregister_netdev(netdev);
-	err = rnpgbe_send_notify(hw, false, mucse_fw_powerup);
+	err = rnpgbe_send_notify(&mucse->hw, false, mucse_fw_powerup);
 	if (err)
 		dev_warn(&pdev->dev, "Send powerdown to hw failed %d\n", err);
 	free_netdev(netdev);
-- 
2.55.0

Re: [PATCH net] net: rnpgbe: Pass an expression directly in rnpgbe_rm_adapter()

[Vadim Fedorenko]

On 12/07/2026 19:35, Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Sun, 12 Jul 2026 20:25:10 +0200
> 
> The address of a data structure member was determined before
> a corresponding null pointer check in the implementation of
> the function “rnpgbe_rm_adapter”.

The null check in rnpgbe_rm_adapter() looks more like defensive
programming, which got into the code unnoticed. pdev will not exist if
netdev is not allocated, where mucse is netdev private data.

Re: net: rnpgbe: Pass an expression directly in rnpgbe_rm_adapter()

[Markus Elfring]

>> The address of a data structure member was determined before
>> a corresponding null pointer check in the implementation of
>> the function “rnpgbe_rm_adapter”.
> 
> The null check in rnpgbe_rm_adapter() looks more like defensive
> programming,

This can be fine, can't it?


>              which got into the code unnoticed.

Some patch reviews happened accordingly.


>                                                 pdev will not exist if
> netdev is not allocated, where mucse is netdev private data.

Would you like to reconsider the relevance of another null pointer check?

Regards,
Markus

Re: [PATCH net] net: rnpgbe: Pass an expression directly in rnpgbe_rm_adapter()

[Dan Carpenter]

On Sun, Jul 12, 2026 at 08:35:21PM +0200, Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Sun, 12 Jul 2026 20:25:10 +0200
> 
> The address of a data structure member was determined before
> a corresponding null pointer check in the implementation of
> the function “rnpgbe_rm_adapter”.
> 
> Thus avoid the risk for undefined behaviour by omitting the variable “hw”.
> Pass the required address directly to a function call.
> 
> This issue was detected by using the Coccinelle software.
> 
> Fixes: 2ee95ec17e97c58b65e978a08b75fa8cb6424e4e ("net: rnpgbe: Add register_netdev")

There is no NULL dereference here.  It's just pointer math.
No need for a Fixes tag.

regards,
dan carpenter

Re: [PATCH net] net: rnpgbe: Pass an expression directly in rnpgbe_rm_adapter()

[Markus Elfring]

>> The address of a data structure member was determined before
>> a corresponding null pointer check in the implementation of
>> the function “rnpgbe_rm_adapter”.
>>
>> Thus avoid the risk for undefined behaviour by omitting the variable “hw”.
>> Pass the required address directly to a function call.
>>
>> This issue was detected by using the Coccinelle software.
>>
>> Fixes: 2ee95ec17e97c58b65e978a08b75fa8cb6424e4e ("net: rnpgbe: Add register_netdev")
> 
> There is no NULL dereference here.  It's just pointer math.
> No need for a Fixes tag.

How does your view fit to information in an article like “Fun with NULL pointers, part 1”(by Jonathan Corbet from 2009-07-20)?
https://lwn.net/Articles/342330/

Regards,
Markus