4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: David Matlack <dmatl...@google.com>
commit cef84c302fe051744b983a92764d3fcca933415d upstream.
KVM's lapic emulation uses static_key_deferred (apic_{hw,sw}_disabled).
These are implemented with delayed_work structs which can still be
pending when the KVM module is unloaded. We've seen this cause kernel
panics when the kvm_intel module is quickly reloaded.
Use the new static_key_deferred_flush() API to flush pending updates on
module unload.
Signed-off-by: David Matlack <dmatl...@google.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/x86/kvm/lapic.c | 6 ++++++
arch/x86/kvm/lapic.h | 1 +
arch/x86/kvm/x86.c | 1 +
3 files changed, 8 insertions(+)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2360,3 +2360,9 @@ void kvm_lapic_init(void)
jump_label_rate_limit(&apic_hw_disabled, HZ);
jump_label_rate_limit(&apic_sw_disabled, HZ);
}
+
+void kvm_lapic_exit(void)
+{
+ static_key_deferred_flush(&apic_hw_disabled);
+ static_key_deferred_flush(&apic_sw_disabled);
+}
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -108,6 +108,7 @@ static inline bool kvm_hv_vapic_assist_p
int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data);
void kvm_lapic_init(void);
+void kvm_lapic_exit(void);
#define VEC_POS(v) ((v) & (32 - 1))
#define REG_POS(v) (((v) >> 5) << 4)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5963,6 +5963,7 @@ out:
void kvm_arch_exit(void)
{
+ kvm_lapic_exit();
perf_unregister_guest_info_callbacks(&kvm_guest_cbs);
if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
