Re: [PATCH net-next v1] e1000: Initialize phy_data to avoid unexpected values

[Rongguang Wei <clementwei90@163.com>]

在 2026/6/13 03:39, Andrew Lunn 写道:
> On Fri, Jun 12, 2026 at 04:03:31PM +0800, Rongguang Wei wrote:
>> From: Rongguang Wei <weirongguang@kylinos.cn>
>>
>> The phy_data variable is not initialized. If e1000_read_phy_reg
>> returns an error, phy_data will not point to a valid value from
>> the PHY register, which may cause the regs_buff array to be populated
>> with unexpected values.
>>
>> Signed-off-by: Rongguang Wei <weirongguang@kylinos.cn>
>> Change-Id: I46071b3b21a566f8da650168d38d6968251b077d
> 
> What does this Change-Id mean?
> 
Sorry, it just a auto generate id when I push this patch on my own repos.
I forget to delete.
>> ---
>>  drivers/net/ethernet/intel/e1000/e1000_ethtool.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
>> index 4dcbeabb3ad2..f068108c5004 100644
>> --- a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
>> +++ b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
>> @@ -327,7 +327,7 @@ static void e1000_get_regs(struct net_device *netdev, struct ethtool_regs *regs,
>>  	struct e1000_adapter *adapter = netdev_priv(netdev);
>>  	struct e1000_hw *hw = &adapter->hw;
>>  	u32 *regs_buff = p;
>> -	u16 phy_data;
>> +	u16 phy_data = 0;
> 
> 	if (hw->phy_type == e1000_phy_igp) {
> 		e1000_write_phy_reg(hw, IGP01E1000_PHY_PAGE_SELECT,
> 				    IGP01E1000_PHY_AGC_A);
> 		e1000_read_phy_reg(hw, IGP01E1000_PHY_AGC_A &
> 				   IGP01E1000_PHY_PAGE_SELECT, &phy_data);
> 		regs_buff[13] = (u32)phy_data; /* cable length */
> 
> Isn't a cable length of 0 also unexpected?
> 
> How does this patch actually make the situation better?
> 
Uninitialized variables may be initialized to 0 by the system, explicit initialization
is performed to avoid accidents. 

The 0 is from e1000_read_phy_reg_ex in e1000_main.c and e1000_power_down_phy when use
e1000_read_phy_reg function the last paramenters is initialized 0. So I used this value.

There are many other function which use e1000_read_phy_reg also not initialize the last paramenters
eg. e1000_phy_reset_clk_and_crs. I can do it in V2.
>     
>     Andrew
> 
> ---
> pw-bot: cr