CVE-2024-26812

In the Linux kernel, the following vulnerability has been resolved:
vfio/pci: Create persistent INTx handler A vulnerability exists where the
eventfd for INTx signaling can be deconfigured, which unregisters the IRQ
handler but still allows eventfds to be signaled with a NULL context
through the SET_IRQS ioctl or through unmask irqfd if the device interrupt
is pending. Ideally this could be solved with some additional locking; the
igate mutex serializes the ioctl and config space accesses, and the
interrupt handler is unregistered relative to the trigger, but the irqfd
path runs asynchronous to those. The igate mutex cannot be acquired from
the atomic context of the eventfd wake function. Disabling the irqfd
relative to the eventfd registration is potentially incompatible with
existing userspace. As a result, the solution implemented here moves
configuration of the INTx interrupt handler to track the lifetime of the
INTx context object and irq_type configuration, rather than registration of
a particular trigger eventfd. Synchronization is added between the ioctl
path and eventfd_signal() wrapper such that the eventfd trigger can be
dynamically updated relative to in-flight interrupts or irqfd callbacks.