| Message ID | 1481927436-104568-2-git-send-email-dmatlack@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
2016-12-16 14:30-0800, David Matlack: > 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 <dmatlack@google.com> > --- Oh, this forgotten bug. I guess that patches to do this automatically from generic module unload code would be over-engineering it ... Reviewed-by: Radim Krčmář <rkrcmar@redhat.com> Thanks. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 34a66b2..1b80fa3 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2426,3 +2426,9 @@ 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); +} diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index e0c8023..ff8039d 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -110,6 +110,7 @@ static inline bool kvm_hv_vapic_assist_page_enabled(struct kvm_vcpu *vcpu) 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) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8f86c0c..da386bf 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6007,6 +6007,7 @@ int kvm_arch_init(void *opaque) void kvm_arch_exit(void) { + kvm_lapic_exit(); perf_unregister_guest_info_callbacks(&kvm_guest_cbs); if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
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 <dmatlack@google.com> --- arch/x86/kvm/lapic.c | 6 ++++++ arch/x86/kvm/lapic.h | 1 + arch/x86/kvm/x86.c | 1 + 3 files changed, 8 insertions(+)