CVE-2026-98712: KVM: arm64: vgic: Take a refcount on IRQs referenced by last_lr_irq
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: vgic: Take a refcount on IRQs referenced by lastlrirq
Referencing the last interrupt inserted in an LR is rather fragile, as this interrupt can vanish if a concurrently unmapped LPI.
Solve this by bumping up the refcount on the interrupt when populating lastlrirq, and drop it at vgicpruneaplist() time, when LPIs are being reclaimed.