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 privcmd_irqfd_assign() and privcmd_irqfd_deassign(). If that happens, it is possible that a kirqfd created and added to the irqfds_list by privcmd_irqfd_assign() may get removed by another thread executing privcmd_irqfd_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.
https://git.kernel.org/stable/c/e997b357b13a7d95de31681fc54fcc34235fa527
https://git.kernel.org/stable/c/611ff1b1ae989a7bcce3e2a8e132ee30e968c557
https://git.kernel.org/stable/c/112fd2f02b308564724b8e81006c254d20945c4b