In the Linux kernel, the following vulnerability has been resolved:

KVM: x86/mmu: Ensure NX huge page recovery thread is alive before waking

When waking a VM's NX huge page recovery thread, ensure the thread is
actually alive before trying to wake it.  Now that the thread is spawned
on-demand during KVM_RUN, a VM without a recovery thread is reachable via
the related module params.

  BUG: kernel NULL pointer dereference, address: 0000000000000040
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:vhost_task_wake+0x5/0x10
  Call Trace:
   <TASK>
   set_nx_huge_pages+0xcc/0x1e0 [kvm]
   param_attr_store+0x8a/0xd0
   module_attr_store+0x1a/0x30
   kernfs_fop_write_iter+0x12f/0x1e0
   vfs_write+0x233/0x3e0
   ksys_write+0x60/0xd0
   do_syscall_64+0x5b/0x160
   entry_SYSCALL_64_after_hwframe+0x4b/0x53
  RIP: 0033:0x7f3b52710104
   </TASK>
  Modules linked in: kvm_intel kvm
  CR2: 0000000000000040