Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

The EVTCHNOP_expand_array hypercall checks for whether FIFO event
channels are enabled, but without holding the correct lock.  It can race
with EVTCHNOP_reset, resulting in dereferencing a NULL pointer.