netdev - Re: [PATCH v2 net] net: phy: phylink: fix uninitialized variable in phylink_get_mac

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Date:   Tue, 26 Feb 2019 19:08:50 +0100
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Russell King - ARM Linux admin <linux@...linux.org.uk>
Cc:     David Miller <davem@...emloft.net>, Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH v2 net] net: phy: phylink: fix uninitialized variable in
 phylink_get_mac_state

On 26.02.2019 09:43, Russell King - ARM Linux admin wrote:
> On Tue, Feb 26, 2019 at 08:25:41AM +0100, Heiner Kallweit wrote:
>> When debugging an issue I found implausible values in state->pause.
>> Reason in that state->pause isn't initialized and later only single
>> bits are changed. Also the struct itself isn't initialized in
>> phylink_resolve(). So better initialize state->pause.
> 
> mac_link_state() is expected to always set this, but this is safer.
> 
I've seen cases where mac_link_state() just initializes the relevant
bits. Therefore there's no functional problem, but it's not nice
(and disturbs in debug output) if all other bits have a random value.

> Maybe also set state->speed to SPEED_UNKNOWN, state->duplex to
> DUPLEX_UNKNOWN and state->an_complete to zero?
> 
OK. Will include this in a v3.

>>
>> v2:
>> - use right function name in subject
>>
>> Fixes: 9525ae83959b ("phylink: add phylink infrastructure")
>> Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
>> ---
>>  drivers/net/phy/phylink.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
>> index 59d175a5b..a9954c205 100644
>> --- a/drivers/net/phy/phylink.c
>> +++ b/drivers/net/phy/phylink.c
>> @@ -324,6 +324,7 @@ static int phylink_get_mac_state(struct phylink *pl, struct phylink_link_state *
>>  	linkmode_zero(state->lp_advertising);
>>  	state->interface = pl->link_config.interface;
>>  	state->an_enabled = pl->link_config.an_enabled;
>> +	state->pause = MLO_PAUSE_NONE;
>>  	state->link = 1;
>>  
>>  	return pl->ops->mac_link_state(ndev, state);
>> -- 
>> 2.20.1
>>
>>
>