Error-state corruption via stale SWERR acknowledgement

Improper register handling in affected Linux kernel releases allows local users to corrupt Intel idxd error state during an interrupt. The process_misc_interrupts function writes the full IDXD_SWERR_ACK mask instead of masking it with the SWERR bits already read, clearing an OVERFLOW bit set by a later error. Exploitation requires low-privileged local access, Intel idxd hardware, and a second device error during the interrupt-handler race; the bounded consequence is loss of the overflow indication.