Fix a bug where KVM attempts to wake a vhost task that has already exited in
response to a fatal signal, and tack on a few cleanups to harden against
introducing similar bugs in the future.
Somehow, this only started causing problems when commit 56180dd20c19 ("futex:
Use RCU-based per-CPU reference counting instead of rcuref_t") landed. I have
no idea why the futex changes exposed the bug, and I don't care all that much,
as this is firmly a KVM bug.
Sean Christopherson (3):
vhost_task: KVM: Don't wake KVM x86's recovery thread if vhost task
was killed
vhost_task: Allow caller to omit handle_sigkill() callback
KVM: x86/mmu: Don't register a sigkill callback for NX hugepage
recovery tasks
arch/x86/kvm/mmu/mmu.c | 9 ++----
include/linux/sched/vhost_task.h | 1 +
kernel/vhost_task.c | 52 +++++++++++++++++++++++++++++---
3 files changed, 51 insertions(+), 11 deletions(-)
base-commit: 1b237f190eb3d36f52dffe07a40b5eb210280e00
--
2.51.0.261.g7ce5a0a67e-goog
