irqchip/gic-v2m: Prevent use after free of gicv2m_get_fwnode()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: irqchip/gic-v2m: Prevent use after free of gicv2m_get_fwnode() With ACPI in place, gicv2m_get_fwnode() is registered with the pci subsystem as pci_msi_get_fwnode_cb(), which may get invoked at runtime during a PCI host bridge probe. But, the call back is wrongly marked as __init, causing it to be freed, while being registered with the PCI subsystem and could trigger: Unable to handle kernel paging request at virtual address ffff8000816c0400 gicv2m_get_fwnode+0x0/0x58 (P) pci_set_bus_msi_domain+0x74/0x88 pci_register_host_bridge+0x194/0x548 This is easily reproducible on a Juno board with ACPI boot. Retain the function for later use.

References

• https://git.kernel.org/stable/c/0c241dedc43a036599757cd08f356253fa3e5014
• https://git.kernel.org/stable/c/b63de43af8d215b0499eac28b2caa4439183efc1
• https://git.kernel.org/stable/c/f95659affee301464f0d058d528d96b35b452da8
• https://git.kernel.org/stable/c/dc0d654eb4179b06d3206e4396d072108b9ba082
• https://git.kernel.org/stable/c/2f2803e4b5e4df2b08d378deaab78b1681ef9b30
• https://git.kernel.org/stable/c/3939d6f29d34cdb60e3f68b76e39e00a964a1d51
• https://git.kernel.org/stable/c/47bee0081b483b077c7560bc5358ad101f89c8ef
• https://git.kernel.org/stable/c/3318dc299b072a0511d6dfd8367f3304fb6d9827