s390/pci: Fix missing check for zpci_create_device() error return

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: s390/pci: Fix missing check for zpci_create_device() error return The zpci_create_device() function returns an error pointer that needs to be checked before dereferencing it as a struct zpci_dev pointer. Add the missing check in __clp_add() where it was missed when adding the scan_list in the fixed commit. Simply not adding the device to the scan list results in the previous behavior.

References

• https://git.kernel.org/stable/c/be54b750c333a9db7c3b3686846bb06b07b011fe
• https://git.kernel.org/stable/c/2769b718e164df983c20c314b263a71a699be6cd
• https://git.kernel.org/stable/c/42420c50c68f3e95e90de2479464f420602229fc