[Intel-wired-lan] [PATCH net resend] ixgbe: fix pci device refcount leak

[Intel-wired-lan] [PATCH net resend] ixgbe: fix pci device refcount leak

[Yang Yingliang]

As comment of pci_get_domain_bus_and_slot() says, it returns
a pci device with refcount increment, when finish using it,
the caller must decrement the reference count by calling
pci_dev_put().

In ixgbe_get_first_secondary_devfn() and ixgbe_x550em_a_has_mii(),
pci_dev_put() is called to avoid leak.

Fixes: 8fa10ef01260 ("ixgbe: register a mdiobus")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
Cc all pepole in the maintainer list.
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c
index 24aa97f993ca..ed0d6a8f239c 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c
@@ -855,9 +855,11 @@ static struct pci_dev *ixgbe_get_first_secondary_devfn(unsigned int devfn)
 	rp_pdev = pci_get_domain_bus_and_slot(0, 0, devfn);
 	if (rp_pdev && rp_pdev->subordinate) {
 		bus = rp_pdev->subordinate->number;
+		pci_dev_put(rp_pdev);
 		return pci_get_domain_bus_and_slot(0, bus, 0);
 	}
 
+	pci_dev_put(rp_pdev);
 	return NULL;
 }
 
@@ -882,6 +884,7 @@ static bool ixgbe_x550em_a_has_mii(struct ixgbe_hw *hw)
 	 * of those two root ports
 	 */
 	func0_pdev = ixgbe_get_first_secondary_devfn(PCI_DEVFN(0x16, 0));
+	pci_dev_put(func0_pdev);
 	if (func0_pdev) {
 		if (func0_pdev == pdev)
 			return true;
@@ -889,6 +892,7 @@ static bool ixgbe_x550em_a_has_mii(struct ixgbe_hw *hw)
 			return false;
 	}
 	func0_pdev = ixgbe_get_first_secondary_devfn(PCI_DEVFN(0x17, 0));
+	pci_dev_put(func0_pdev);
 	if (func0_pdev == pdev)
 		return true;
 
-- 
2.25.1

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Re: [Intel-wired-lan] [PATCH net resend] ixgbe: fix pci device refcount leak

[Tony Nguyen]

On 11/21/2022 10:08 PM, Yang Yingliang wrote:
> As comment of pci_get_domain_bus_and_slot() says, it returns
> a pci device with refcount increment, when finish using it,
> the caller must decrement the reference count by calling
> pci_dev_put().
> 
> In ixgbe_get_first_secondary_devfn() and ixgbe_x550em_a_has_mii(),
> pci_dev_put() is called to avoid leak.
> 
> Fixes: 8fa10ef01260 ("ixgbe: register a mdiobus")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---

<snip>

> @@ -882,6 +884,7 @@ static bool ixgbe_x550em_a_has_mii(struct ixgbe_hw *hw)
>   	 * of those two root ports
>   	 */
>   	func0_pdev = ixgbe_get_first_secondary_devfn(PCI_DEVFN(0x16, 0));
> +	pci_dev_put(func0_pdev);
>   	if (func0_pdev) {
>   		if (func0_pdev == pdev)
>   			return true;
> @@ -889,6 +892,7 @@ static bool ixgbe_x550em_a_has_mii(struct ixgbe_hw *hw)
>   			return false;
>   	}
>   	func0_pdev = ixgbe_get_first_secondary_devfn(PCI_DEVFN(0x17, 0));
> +	pci_dev_put(func0_pdev);
>   	if (func0_pdev == pdev)
>   		return true;

It would probably be better to defer these puts until after the checks 
and values are set. I'd think some local vars and gotos may be cleaner 
than placing puts before all the returns.

Thanks,
Tony
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