In the Linux kernel, the following vulnerability has been resolved:
xen: privcmd: Fix possible access to a freed kirqfd instance
Nothing prevents simultaneous ioctl calls to privcmdirqfdassign() and privcmdirqfddeassign(). If that happens, it is possible that a kirqfd created and added to the irqfdslist by privcmdirqfdassign() may get removed by another thread executing privcmdirqfd_deassign(), while the former is still using it after dropping the locks.
This can lead to a situation where an already freed kirqfd instance may be accessed and cause kernel oops.
Use SRCU locking to prevent the same, as is done for the KVM implementation for irqfds.