From 11e1f669ef6b094c5761982bfbaa9a81feec2fbd Mon Sep 17 00:00:00 2001 From: David Matlack Date: Fri, 16 Dec 2016 14:30:36 -0800 Subject: [PATCH] KVM: x86: flush pending lapic jump label updates on module unload BugLink: http://bugs.launchpad.net/bugs/1658091 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 Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman Signed-off-by: Tim Gardner Signed-off-by: Luis Henriques --- arch/x86/kvm/lapic.c | 6 ++++++ arch/x86/kvm/lapic.h | 1 + arch/x86/kvm/x86.c | 1 + 3 files changed, 8 insertions(+) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 36591faed13b..d850a04d61cc 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2193,3 +2193,9 @@ 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 41bdb35b4b67..002919a9ae12 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -95,6 +95,7 @@ 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); static inline u32 kvm_apic_get_reg(struct kvm_lapic *apic, int reg_off) { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 58e15ad86bfb..465d0e2d9a59 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5872,6 +5872,7 @@ 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)) -- 2.39.5