CVE-2026-23085

In the Linux kernel, the following vulnerability has been resolved:

irqchip/gic-v3-its: Avoid truncating memory addresses

On 32-bit machines with CONFIG_ARM_LPAE, it is possible for lowmem

allocations to be backed by addresses physical memory above the 32-bit

address limit, as found while experimenting with larger VMSPLIT

configurations.

This caused the qemu virt model to crash in the GICv3 driver, which

allocates the 'itt' object using GFP_KERNEL. Since all memory below

the 4GB physical address limit is in ZONE_DMA in this configuration,

kmalloc() defaults to higher addresses for ZONE_NORMAL, and the

ITS driver stores the physical address in a 32-bit 'unsigned long'

variable.

Change the itt_addr variable to the correct phys_addr_t type instead,

along with all other variables in this driver that hold a physical

address.

The gicv5 driver correctly uses u64 variables, while all other irqchip

drivers don't call virt_to_phys or similar interfaces. It's expected that

other device drivers have similar issues, but fixing this one is

sufficient for booting a virtio based guest.