Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936731AbdCJMnj (ORCPT ); Fri, 10 Mar 2017 07:43:39 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:45079 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936421AbdCJMMU (ORCPT ); Fri, 10 Mar 2017 07:12:20 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Paolo Bonzini" , "David Matlack" Date: Fri, 10 Mar 2017 11:46:23 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 220/370] KVM: x86: flush pending lapic jump label updates on module unload In-Reply-To: X-SA-Exim-Connect-IP: 82.70.136.246 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1710 Lines: 57 3.16.42-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: David Matlack 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: Ben Hutchings --- 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 @@ -1941,3 +1941,9 @@ 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 @@ -93,6 +93,7 @@ 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); static inline u32 kvm_apic_get_reg(struct kvm_lapic *apic, int reg_off) { --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5677,6 +5677,7 @@ 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))