Patchwork p54pci: don't return zero on failure path in p54p_probe()

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Submitter Alexey Khoroshilov
Date Jan. 1, 2013, 9:11 p.m.
Message ID <1357074661-15784-1-git-send-email-khoroshilov@ispras.ru>
Download mbox | patch
Permalink /patch/208963/
State Not Applicable
Delegated to: David Miller
Headers show

Comments

Alexey Khoroshilov - Jan. 1, 2013, 9:11 p.m.
If pci_set_dma_mask() or pci_set_consistent_dma_mask() fails in p54p_probe(),
it breaks off initialization, deallocates all resources, but returns zero.

The patch implements proper error code propagation.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
---
 drivers/net/wireless/p54/p54pci.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
Christian Lamparter - Jan. 1, 2013, 9:45 p.m.
On Tuesday 01 January 2013 22:11:01 Alexey Khoroshilov wrote:
> If pci_set_dma_mask() or pci_set_consistent_dma_mask() fails in p54p_probe(),
> it breaks off initialization, deallocates all resources, but returns zero.
> 
> The patch implements proper error code propagation.

Uh, Thanks!

But wait, I think there's another return 0 in the error
path. See p54pci.c @ line 558:

mem_len = pci_resource_len(pdev, 0);
if (mem_len < sizeof(...)) {
	dev_err(...)
	goto err_disabled_dev;
}

Do you think you can add a err = -EINVAL; before the goto too?
[I wonder why this wasn't found by the verification project as
well? Could it be that pci_resource_len(...) < sizeof(...) is 
somehow always true and this is a dead branch?]

> Found by Linux Driver Verification project (linuxtesting.org).
> 
> Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Christian Lamparter <chunkeey@googlemail.com>

Regards,
	Christian
> ---
>  drivers/net/wireless/p54/p54pci.c |    6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/p54/p54pci.c b/drivers/net/wireless/p54/p54pci.c
> index 933e5d9..fef69ea 100644
> --- a/drivers/net/wireless/p54/p54pci.c
> +++ b/drivers/net/wireless/p54/p54pci.c
> @@ -568,8 +568,10 @@ static int p54p_probe(struct pci_dev *pdev,
>  		goto err_disable_dev;
>  	}
>  
> -	if (pci_set_dma_mask(pdev, DMA_BIT_MASK(32)) ||
> -	    pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32))) {
> +	err = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
> +	if (!err)
> +		err = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
> +	if (err) {
>  		dev_err(&pdev->dev, "No suitable DMA available\n");
>  		goto err_free_reg;
>  	}
> 


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Alexey Khoroshilov - Jan. 1, 2013, 10:44 p.m.
On 01/02/2013 01:45 AM, Christian Lamparter wrote:
> On Tuesday 01 January 2013 22:11:01 Alexey Khoroshilov wrote:
>> If pci_set_dma_mask() or pci_set_consistent_dma_mask() fails in p54p_probe(),
>> it breaks off initialization, deallocates all resources, but returns zero.
>>
>> The patch implements proper error code propagation.
> Uh, Thanks!
>
> But wait, I think there's another return 0 in the error
> path. See p54pci.c @ line 558:
>
> mem_len = pci_resource_len(pdev, 0);
> if (mem_len < sizeof(...)) {
> 	dev_err(...)
> 	goto err_disabled_dev;
> }
>
> Do you think you can add a err = -EINVAL; before the goto too?
You are right! But I would say -ENODEV is more popular error code in 
this case.
> [I wonder why this wasn't found by the verification project as
> well? Could it be that pci_resource_len(...) < sizeof(...) is
> somehow always true and this is a dead branch?]
Actually it was found, but I have no direct access to the results at the 
moment. My fault.

Would you like I resend the patch to fix both?

--
Best regards,
Alexey

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Christian Lamparter - Jan. 1, 2013, 11:53 p.m.
On Tuesday 01 January 2013 23:44:38 Alexey Khoroshilov wrote:
> On 01/02/2013 01:45 AM, Christian Lamparter wrote:
> > On Tuesday 01 January 2013 22:11:01 Alexey Khoroshilov wrote:
> >> If pci_set_dma_mask() or pci_set_consistent_dma_mask() fails in p54p_probe(),
> >> it breaks off initialization, deallocates all resources, but returns zero.
> >>
> >> The patch implements proper error code propagation.
> > Uh, Thanks!
> >
> > But wait, I think there's another return 0 in the error
> > path. See p54pci.c @ line 558:
> >
> > mem_len = pci_resource_len(pdev, 0);
> > if (mem_len < sizeof(...)) {
> > 	dev_err(...)
> > 	goto err_disabled_dev;
> > }
> >
> > Do you think you can add a err = -EINVAL; before the goto too?
> You are right! But I would say -ENODEV is more popular error code in 
> this case.
pci_* functions seem to use a lot of -EIO too. Either way shouldn't
really matter. So, let's make it -ENODEV.
 
> > [I wonder why this wasn't found by the verification project as
> > well? Could it be that pci_resource_len(...) < sizeof(...) is
> > somehow always true and this is a dead branch?]
> Actually it was found, but I have no direct access to the results at the 
> moment. My fault.
> 
> Would you like I resend the patch to fix both?
:)

Don't forget the ACKed-by tag from the previous reply!

Thanks

Christian
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Patch

diff --git a/drivers/net/wireless/p54/p54pci.c b/drivers/net/wireless/p54/p54pci.c
index 933e5d9..fef69ea 100644
--- a/drivers/net/wireless/p54/p54pci.c
+++ b/drivers/net/wireless/p54/p54pci.c
@@ -568,8 +568,10 @@  static int p54p_probe(struct pci_dev *pdev,
 		goto err_disable_dev;
 	}
 
-	if (pci_set_dma_mask(pdev, DMA_BIT_MASK(32)) ||
-	    pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32))) {
+	err = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
+	if (!err)
+		err = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
+	if (err) {
 		dev_err(&pdev->dev, "No suitable DMA available\n");
 		goto err_free_reg;
 	}