In the Linux kernel, the following vulnerability has been resolved:
KVM: s390: Take srcu when importing watchpoint data
__import_wp_info() backs up the original guest memory contents of a
watchpoint with read_guest_abs(), which is kvm_read_guest() and therefore
resolves the memslot via __kvm_memslots(). That requires kvm->srcu (or
kvm->slots_lock) to be held, otherwise a concurrent memslot update can
free the memslots array under us once its SRCU grace period has elapsed.
As this is not fast path, following lock ordering (mutex first, then
srcu) take the big hammer and hold the srcu for the full import.
