[PATCH v2 net] net: phy: phylink: fix uninitialized variable in phylink_get_mac_state

[PATCH v2 net] net: phy: phylink: fix uninitialized variable in phylink_get_mac_state

[Heiner Kallweit]

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.

v2:
- use right function name in subject

Fixes: 9525ae83959b ("phylink: add phylink infrastructure")
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.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

Re: [PATCH v2 net] net: phy: phylink: fix uninitialized variable in phylink_get_mac_state

[Russell King - ARM Linux admin]

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.

Maybe also set state->speed to SPEED_UNKNOWN, state->duplex to
DUPLEX_UNKNOWN and state->an_complete to zero?

> 
> v2:
> - use right function name in subject
> 
> Fixes: 9525ae83959b ("phylink: add phylink infrastructure")
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.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
> 
> 

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

[Heiner Kallweit]

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@gmail.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
>>
>>
>