linux-kernel - Re: [PATCH] pci/hotplug: fix potential memory leak in disable

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Date:   Mon, 22 Mar 2021 10:42:33 +0100
From:   Niklas Schnelle <schnelle@...ux.ibm.com>
To:     Zhiqiang Liu <liuzhiqiang26@...wei.com>
Cc:     linux-s390@...r.kernel.org, linux-pci@...r.kernel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        linfeilong <linfeilong@...wei.com>,
        gerald.schaefer@...ux.ibm.com, bhelgaas@...gle.com
Subject: Re: [PATCH] pci/hotplug: fix potential memory leak in disable_slot()



On 21/03/2021 16:51, Zhiqiang Liu wrote:
> 
> In disable_slot(), if we obtain desired PCI device
> successfully by calling pci_get_slot(), we should
> call pci_dev_put() to release its reference.

Thanks for the patch! This should however be fixed independently by 
commit 0b13525c20fe ("s390/pci: fix leak of PCI device structure")
which was just added to v5.12-rc4 and will be backported to stable.
There were a few similar cases that also got fixed by that commit.

> 
> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@...wei.com>
> Signed-off-by: Feilong Lin <linfeilong@...wei.com>
> ---
>   drivers/pci/hotplug/s390_pci_hpc.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/hotplug/s390_pci_hpc.c b/drivers/pci/hotplug/s390_pci_hpc.c
> index c9e790c74051..999a34b6fd50 100644
> --- a/drivers/pci/hotplug/s390_pci_hpc.c
> +++ b/drivers/pci/hotplug/s390_pci_hpc.c
> @@ -89,9 +89,11 @@ static int disable_slot(struct hotplug_slot *hotplug_slot)
>   		return -EIO;
> 
>   	pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);
> -	if (pdev && pci_num_vf(pdev)) {
> +	if (pdev) {
> +		rc = pci_num_vf(pdev);
>   		pci_dev_put(pdev);
> -		return -EBUSY;
> +		if (rc)
> +			return -EBUSY;
>   	}
> 
>   	zpci_remove_device(zdev);
>