[PATCH net-next v2] qlcnic: check pci_reset_function result

[PATCH net-next v2] qlcnic: check pci_reset_function result

[Denis Plotnikov]

Static code analyzer complains to unchecked return value.
The result of pci_reset_function() is unchecked.
Despite, the issue is on the FLR supported code path and in that
case reset can be done with pcie_flr(), the patch uses less invasive
approach by adding the result check of pci_reset_function().

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 7e2cf4feba05 ("qlcnic: change driver hardware interface mechanism")
Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru>
---
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c
index 87f76bac2e463..eb827b86ecae8 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c
@@ -628,7 +628,13 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev)
 	int i, err, ring;
 
 	if (dev->flags & QLCNIC_NEED_FLR) {
-		pci_reset_function(dev->pdev);
+		err = pci_reset_function(dev->pdev);
+		if (err) {
+			dev_err(&dev->pdev->dev,
+				"Adapter reset failed (%d). Please reboot\n",
+				err);
+			return err;
+		}
 		dev->flags &= ~QLCNIC_NEED_FLR;
 	}
 
-- 
2.25.1

Re: [PATCH net-next v2] qlcnic: check pci_reset_function result

[Simon Horman]

On Fri, Apr 07, 2023 at 10:18:49AM +0300, Denis Plotnikov wrote:
> Static code analyzer complains to unchecked return value.
> The result of pci_reset_function() is unchecked.
> Despite, the issue is on the FLR supported code path and in that
> case reset can be done with pcie_flr(), the patch uses less invasive
> approach by adding the result check of pci_reset_function().
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 7e2cf4feba05 ("qlcnic: change driver hardware interface mechanism")
> Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru>

Thanks Denis,

With reference to,

Link: https://lore.kernel.org/all/20230405193708.GA3632282@bhelgaas/

I think this is the best approach in lieu of feedback from those
with knowledge of the hardware / testing on the hardware.

Reviewed-by: Simon Horman <simon.horman@corigine.com>

> ---
>  drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c
> index 87f76bac2e463..eb827b86ecae8 100644
> --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c
> +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c
> @@ -628,7 +628,13 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev)
>  	int i, err, ring;
>  
>  	if (dev->flags & QLCNIC_NEED_FLR) {
> -		pci_reset_function(dev->pdev);
> +		err = pci_reset_function(dev->pdev);
> +		if (err) {
> +			dev_err(&dev->pdev->dev,
> +				"Adapter reset failed (%d). Please reboot\n",
> +				err);
> +			return err;
> +		}
>  		dev->flags &= ~QLCNIC_NEED_FLR;
>  	}
>  
> -- 
> 2.25.1
> 

Re: [PATCH net-next v2] qlcnic: check pci_reset_function result

[Bjorn Helgaas]

On Fri, Apr 07, 2023 at 11:01:14AM +0200, Simon Horman wrote:
> On Fri, Apr 07, 2023 at 10:18:49AM +0300, Denis Plotnikov wrote:
> > Static code analyzer complains to unchecked return value.
> > The result of pci_reset_function() is unchecked.
> > Despite, the issue is on the FLR supported code path and in that
> > case reset can be done with pcie_flr(), the patch uses less invasive
> > approach by adding the result check of pci_reset_function().

Text could possibly be smoothed out a bit, e.g.:

  Static code analyzer complains that the result of
  pci_reset_function() is unchecked.  Check it and return error if
  it fails because the driver relies on the device being reset.

> > Found by Linux Verification Center (linuxtesting.org) with SVACE.
> > 
> > Fixes: 7e2cf4feba05 ("qlcnic: change driver hardware interface mechanism")
> > Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru>
> 
> Thanks Denis,
> 
> With reference to,
> 
> Link: https://lore.kernel.org/all/20230405193708.GA3632282@bhelgaas/
> 
> I think this is the best approach in lieu of feedback from those
> with knowledge of the hardware / testing on the hardware.

Agreed, looks good to me, too.  It doesn't look like there's much
activity in this driver (except wider-scale cleanups, etc), so I doubt
anybody could be confident that relying pcie_flr() would be safe.

Seem a *little* weird that this reset is done in .ndo_open() instead
of once at probe-time, but that's a much bigger question and not worth
worrying about.

Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>

> Reviewed-by: Simon Horman <simon.horman@corigine.com>
> 
> > ---
> >  drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c
> > index 87f76bac2e463..eb827b86ecae8 100644
> > --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c
> > +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c
> > @@ -628,7 +628,13 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev)
> >  	int i, err, ring;
> >  
> >  	if (dev->flags & QLCNIC_NEED_FLR) {
> > -		pci_reset_function(dev->pdev);
> > +		err = pci_reset_function(dev->pdev);
> > +		if (err) {
> > +			dev_err(&dev->pdev->dev,
> > +				"Adapter reset failed (%d). Please reboot\n",
> > +				err);
> > +			return err;
> > +		}
> >  		dev->flags &= ~QLCNIC_NEED_FLR;
> >  	}
> >  
> > -- 
> > 2.25.1
> > 

Re: [PATCH net-next v2] qlcnic: check pci_reset_function result

[Paolo Abeni]

On Fri, 2023-04-07 at 10:18 +0300, Denis Plotnikov wrote:
> Static code analyzer complains to unchecked return value.
> The result of pci_reset_function() is unchecked.
> Despite, the issue is on the FLR supported code path and in that
> case reset can be done with pcie_flr(), the patch uses less invasive
> approach by adding the result check of pci_reset_function().
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 7e2cf4feba05 ("qlcnic: change driver hardware interface mechanism")
> Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru>

Any special reason to target the net-next tree? This looks like a -net
candidate to me?

Thanks!

Paolo

Re: [PATCH net-next v2] qlcnic: check pci_reset_function result

[Simon Horman]

On Tue, Apr 11, 2023 at 01:24:33PM +0200, Paolo Abeni wrote:
> On Fri, 2023-04-07 at 10:18 +0300, Denis Plotnikov wrote:
> > Static code analyzer complains to unchecked return value.
> > The result of pci_reset_function() is unchecked.
> > Despite, the issue is on the FLR supported code path and in that
> > case reset can be done with pcie_flr(), the patch uses less invasive
> > approach by adding the result check of pci_reset_function().
> > 
> > Found by Linux Verification Center (linuxtesting.org) with SVACE.
> > 
> > Fixes: 7e2cf4feba05 ("qlcnic: change driver hardware interface mechanism")
> > Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru>
> 
> Any special reason to target the net-next tree? This looks like a -net
> candidate to me?

FWIIW, net would be fine by me.
Sorry for not noticing this during earlier review.

Re: [PATCH net-next v2] qlcnic: check pci_reset_function result

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Fri,  7 Apr 2023 10:18:49 +0300 you wrote:
> Static code analyzer complains to unchecked return value.
> The result of pci_reset_function() is unchecked.
> Despite, the issue is on the FLR supported code path and in that
> case reset can be done with pcie_flr(), the patch uses less invasive
> approach by adding the result check of pci_reset_function().
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> [...]

Here is the summary with links:
  - [net-next,v2] qlcnic: check pci_reset_function result
    https://git.kernel.org/netdev/net/c/7573099e10ca

You are awesome, thank you!
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