Linux Kernel PCI IRQ Domain NULL Pointer Dereference Vulnerability in rcar-host Controller

A vulnerability in the Linux kernel's PCI handling for the rcar-host controller can lead to a NULL pointer dereference. This issue arises because the MSI parent IRQ domain is not properly set, causing a kernel error when the IRQ domain is accessed. The vulnerability was introduced in a recent commit that changed how MSI IRQ domains are managed, and it was not detected during testing on hardware with the affected PCIe controller.

Impact

Exploitation of this vulnerability causes a kernel NULL pointer dereference, leading to a crash of the affected system.