[PATCH net-next] net: txgbe: Avoid passing uninitialised parameter to pci_wake_from_d3()

[PATCH net-next] net: txgbe: Avoid passing uninitialised parameter to pci_wake_from_d3()

[Simon Horman]

txgbe_shutdown() relies on txgbe_dev_shutdown() to initialise
wake by passing it by reference. However, txgbe_dev_shutdown()
doesn't use this parameter at all.

wake is then passed uninitialised by txgbe_dev_shutdown()
to pci_wake_from_d3().

Resolve this problem by:
* Removing the unused parameter from txgbe_dev_shutdown()
* Removing the uninitialised variable wake from txgbe_dev_shutdown()
* Passing false to pci_wake_from_d3() - this assumes that
  although uninitialised wake was in practice false (0).

I'm not sure that this counts as a bug, as I'm not sure that
it manifests in any unwanted behaviour. But in any case, the issue
was introduced by:

  bbd22f34b47c ("net: txgbe: Avoid passing uninitialised parameter to pci_wake_from_d3()")

Flagged by Smatch as:

  .../txgbe_main.c:486 txgbe_shutdown() error: uninitialized symbol 'wake'.

No functional change intended.
Compile tested only.

Signed-off-by: Simon Horman <horms@kernel.org>
---
 drivers/net/ethernet/wangxun/txgbe/txgbe_main.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c b/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
index 0f0d9fa1cde1..cfe47f3d2503 100644
--- a/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
+++ b/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
@@ -457,7 +457,7 @@ static int txgbe_close(struct net_device *netdev)
 	return 0;
 }
 
-static void txgbe_dev_shutdown(struct pci_dev *pdev, bool *enable_wake)
+static void txgbe_dev_shutdown(struct pci_dev *pdev)
 {
 	struct wx *wx = pci_get_drvdata(pdev);
 	struct net_device *netdev;
@@ -477,12 +477,10 @@ static void txgbe_dev_shutdown(struct pci_dev *pdev, bool *enable_wake)
 
 static void txgbe_shutdown(struct pci_dev *pdev)
 {
-	bool wake;
-
-	txgbe_dev_shutdown(pdev, &wake);
+	txgbe_dev_shutdown(pdev);
 
 	if (system_state == SYSTEM_POWER_OFF) {
-		pci_wake_from_d3(pdev, wake);
+		pci_wake_from_d3(pdev, false);
 		pci_set_power_state(pdev, PCI_D3hot);
 	}
 }

Re: [PATCH net-next] net: txgbe: Avoid passing uninitialised parameter to pci_wake_from_d3()

[Dan Carpenter]

On Mon, Jun 05, 2023 at 04:20:28PM +0200, Simon Horman wrote:
> txgbe_shutdown() relies on txgbe_dev_shutdown() to initialise
> wake by passing it by reference. However, txgbe_dev_shutdown()
> doesn't use this parameter at all.
> 
> wake is then passed uninitialised by txgbe_dev_shutdown()
> to pci_wake_from_d3().
> 
> Resolve this problem by:
> * Removing the unused parameter from txgbe_dev_shutdown()
> * Removing the uninitialised variable wake from txgbe_dev_shutdown()
> * Passing false to pci_wake_from_d3() - this assumes that
>   although uninitialised wake was in practice false (0).
> 
> I'm not sure that this counts as a bug, as I'm not sure that
> it manifests in any unwanted behaviour. But in any case, the issue
> was introduced by:
> 
>   bbd22f34b47c ("net: txgbe: Avoid passing uninitialised parameter to pci_wake_from_d3()")
> 
> Flagged by Smatch as:
> 
>   .../txgbe_main.c:486 txgbe_shutdown() error: uninitialized symbol 'wake'.
> 
> No functional change intended.
> Compile tested only.
> 

Almost everyone turns on the AUTO_VAR_INIT stuff these days so that's
why we don't see these bugs in testing but they are still bugs and they
will affect people who have that turned off.

CONFIG_CC_HAS_AUTO_VAR_INIT_PATTERN=y
CONFIG_CC_HAS_AUTO_VAR_INIT_ZERO_BARE=y
CONFIG_CC_HAS_AUTO_VAR_INIT_ZERO=y
# CONFIG_INIT_STACK_NONE is not set
CONFIG_INIT_STACK_ALL_PATTERN=y
# CONFIG_INIT_STACK_ALL_ZERO is not set
CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
CONFIG_INIT_ON_FREE_DEFAULT_ON=y

I did report this bug, but I only sent it to the original author and I
CC'd kernel-janitors.  In 2009 when Smatch was quite new the netdev list
was annoyed by static analysis bug reports so I stopped CCing netdev.

https://lore.kernel.org/all/YsWWXYal9ZwmIo2G@kili/

regards,
dan carpenter

Re: [PATCH net-next] net: txgbe: Avoid passing uninitialised parameter to pci_wake_from_d3()

[Maciej Fijalkowski]

On Mon, Jun 05, 2023 at 04:20:28PM +0200, Simon Horman wrote:

Hey Simon,

> txgbe_shutdown() relies on txgbe_dev_shutdown() to initialise
> wake by passing it by reference. However, txgbe_dev_shutdown()
> doesn't use this parameter at all.
> 
> wake is then passed uninitialised by txgbe_dev_shutdown()
> to pci_wake_from_d3().
> 
> Resolve this problem by:
> * Removing the unused parameter from txgbe_dev_shutdown()
> * Removing the uninitialised variable wake from txgbe_dev_shutdown()
> * Passing false to pci_wake_from_d3() - this assumes that
>   although uninitialised wake was in practice false (0).
> 
> I'm not sure that this counts as a bug, as I'm not sure that
> it manifests in any unwanted behaviour. But in any case, the issue
> was introduced by:
> 
>   bbd22f34b47c ("net: txgbe: Avoid passing uninitialised parameter to pci_wake_from_d3()")

wait, you are pointing to your own commit here?

this supposed to be:
3ce7547e5b71 net: txgbe: Add build support for txgbe

no?

> 
> Flagged by Smatch as:
> 
>   .../txgbe_main.c:486 txgbe_shutdown() error: uninitialized symbol 'wake'.
> 
> No functional change intended.
> Compile tested only.
> 
> Signed-off-by: Simon Horman <horms@kernel.org>
> ---
>  drivers/net/ethernet/wangxun/txgbe/txgbe_main.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c b/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
> index 0f0d9fa1cde1..cfe47f3d2503 100644
> --- a/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
> +++ b/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
> @@ -457,7 +457,7 @@ static int txgbe_close(struct net_device *netdev)
>  	return 0;
>  }
>  
> -static void txgbe_dev_shutdown(struct pci_dev *pdev, bool *enable_wake)
> +static void txgbe_dev_shutdown(struct pci_dev *pdev)
>  {
>  	struct wx *wx = pci_get_drvdata(pdev);
>  	struct net_device *netdev;
> @@ -477,12 +477,10 @@ static void txgbe_dev_shutdown(struct pci_dev *pdev, bool *enable_wake)
>  
>  static void txgbe_shutdown(struct pci_dev *pdev)
>  {
> -	bool wake;
> -
> -	txgbe_dev_shutdown(pdev, &wake);
> +	txgbe_dev_shutdown(pdev);
>  
>  	if (system_state == SYSTEM_POWER_OFF) {
> -		pci_wake_from_d3(pdev, wake);
> +		pci_wake_from_d3(pdev, false);
>  		pci_set_power_state(pdev, PCI_D3hot);
>  	}
>  }
> 
> 

Re: [PATCH net-next] net: txgbe: Avoid passing uninitialised parameter to pci_wake_from_d3()

[Simon Horman]

On Mon, Jun 05, 2023 at 08:22:38PM +0200, Maciej Fijalkowski wrote:
> On Mon, Jun 05, 2023 at 04:20:28PM +0200, Simon Horman wrote:
> 
> Hey Simon,
> 
> > txgbe_shutdown() relies on txgbe_dev_shutdown() to initialise
> > wake by passing it by reference. However, txgbe_dev_shutdown()
> > doesn't use this parameter at all.
> > 
> > wake is then passed uninitialised by txgbe_dev_shutdown()
> > to pci_wake_from_d3().
> > 
> > Resolve this problem by:
> > * Removing the unused parameter from txgbe_dev_shutdown()
> > * Removing the uninitialised variable wake from txgbe_dev_shutdown()
> > * Passing false to pci_wake_from_d3() - this assumes that
> >   although uninitialised wake was in practice false (0).
> > 
> > I'm not sure that this counts as a bug, as I'm not sure that
> > it manifests in any unwanted behaviour. But in any case, the issue
> > was introduced by:
> > 
> >   bbd22f34b47c ("net: txgbe: Avoid passing uninitialised parameter to pci_wake_from_d3()")
> 
> wait, you are pointing to your own commit here?
> 
> this supposed to be:
> 3ce7547e5b71 net: txgbe: Add build support for txgbe
> 
> no?

Yes, sorry about that.

Will fix in a v2.

...

-- 
pw-bot: cr

RE: [PATCH net-next] net: txgbe: Avoid passing uninitialised parameter to pci_wake_from_d3()

[Jiawen Wu]

On Monday, June 5, 2023 10:20 PM, Simon Horman wrote:
> txgbe_shutdown() relies on txgbe_dev_shutdown() to initialise
> wake by passing it by reference. However, txgbe_dev_shutdown()
> doesn't use this parameter at all.
> 
> wake is then passed uninitialised by txgbe_dev_shutdown()
> to pci_wake_from_d3().
> 
> Resolve this problem by:
> * Removing the unused parameter from txgbe_dev_shutdown()
> * Removing the uninitialised variable wake from txgbe_dev_shutdown()
> * Passing false to pci_wake_from_d3() - this assumes that
>   although uninitialised wake was in practice false (0).
> 
> I'm not sure that this counts as a bug, as I'm not sure that
> it manifests in any unwanted behaviour. But in any case, the issue
> was introduced by:

Thanks for the fix. These are some redundant codes for a feature that has
not yet been implemented.
Reviewed-by: Jiawen Wu <jiawenwu@trustnetic.com>

> 
>   bbd22f34b47c ("net: txgbe: Avoid passing uninitialised parameter to pci_wake_from_d3()")
> 
> Flagged by Smatch as:
> 
>   .../txgbe_main.c:486 txgbe_shutdown() error: uninitialized symbol 'wake'.
> 
> No functional change intended.
> Compile tested only.
> 
> Signed-off-by: Simon Horman <horms@kernel.org>
> ---
>  drivers/net/ethernet/wangxun/txgbe/txgbe_main.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c b/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
> index 0f0d9fa1cde1..cfe47f3d2503 100644
> --- a/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
> +++ b/drivers/net/ethernet/wangxun/txgbe/txgbe_main.c
> @@ -457,7 +457,7 @@ static int txgbe_close(struct net_device *netdev)
>  	return 0;
>  }
> 
> -static void txgbe_dev_shutdown(struct pci_dev *pdev, bool *enable_wake)
> +static void txgbe_dev_shutdown(struct pci_dev *pdev)
>  {
>  	struct wx *wx = pci_get_drvdata(pdev);
>  	struct net_device *netdev;
> @@ -477,12 +477,10 @@ static void txgbe_dev_shutdown(struct pci_dev *pdev, bool *enable_wake)
> 
>  static void txgbe_shutdown(struct pci_dev *pdev)
>  {
> -	bool wake;
> -
> -	txgbe_dev_shutdown(pdev, &wake);
> +	txgbe_dev_shutdown(pdev);
> 
>  	if (system_state == SYSTEM_POWER_OFF) {
> -		pci_wake_from_d3(pdev, wake);
> +		pci_wake_from_d3(pdev, false);
>  		pci_set_power_state(pdev, PCI_D3hot);
>  	}
>  }