Re: [PATCH v2 1/3] PCI/sysfs: Fix null pointer dereference during hotplug

[Bjorn Helgaas]

On Wed, Dec 24, 2025 at 05:27:17PM +0800, Ziming Du wrote:
> During the concurrent process of creating and rescanning in VF, the
> resource files for the same pci_dev may be created twice. The second
> creation attempt fails, resulting the res_attr in pci_dev to kfree(),
> but the pointer is not set to NULL. This will subsequently lead to
> dereferencing a null pointer when removing the device.
> 
> When we perform the following operation:
>   echo $vfcount > /sys/class/net/"$pfname"/device/sriov_numvfs &

Is the value of $vfcount relevant here?  Can you use the actual values
here instead of the variables so this is more useful to others?

>   sleep 0.5
>   echo 1 > /sys/bus/pci/rescan
>   pci_remove "$pfname"
> system will crash as follows: