srcu_idx is easy to misuse as it can not be used in nested srcu_read_lock calls. Switch to local index to make correctness easier to verify.
Signed-off-by: Michael S. Tsirkin <[email protected]> --- OK, this works for me. Pls apply. arch/x86/kvm/x86.c | 28 ++++++++++++++-------------- 1 files changed, 14 insertions(+), 14 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4ca1d7f..d76d142 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4672,7 +4672,7 @@ static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu) } } -static int vcpu_enter_guest(struct kvm_vcpu *vcpu) +static int vcpu_enter_guest(struct kvm_vcpu *vcpu, int *srcu_idx) { int r; bool req_int_win = !irqchip_in_kernel(vcpu->kvm) && @@ -4744,7 +4744,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) kvm_lapic_sync_to_vapic(vcpu); } - srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); + srcu_read_unlock(&vcpu->kvm->srcu, *srcu_idx); kvm_guest_enter(); @@ -4787,7 +4787,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) preempt_enable(); - vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); + *srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); /* * Profile KVM exit RIPs: @@ -4808,7 +4808,7 @@ out: static int __vcpu_run(struct kvm_vcpu *vcpu) { - int r; + int srcu_idx, r; struct kvm *kvm = vcpu->kvm; if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_SIPI_RECEIVED)) { @@ -4821,17 +4821,17 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; } - vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); + srcu_idx = srcu_read_lock(&kvm->srcu); vapic_enter(vcpu); r = 1; while (r > 0) { if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE) - r = vcpu_enter_guest(vcpu); + r = vcpu_enter_guest(vcpu, &srcu_idx); else { - srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); + srcu_read_unlock(&kvm->srcu, srcu_idx); kvm_vcpu_block(vcpu); - vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); + srcu_idx = srcu_read_lock(&kvm->srcu); if (kvm_check_request(KVM_REQ_UNHALT, vcpu)) { switch(vcpu->arch.mp_state) { @@ -4866,13 +4866,13 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) ++vcpu->stat.signal_exits; } if (need_resched()) { - srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); + srcu_read_unlock(&kvm->srcu, srcu_idx); kvm_resched(vcpu); - vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); + srcu_idx = srcu_read_lock(&kvm->srcu); } } - srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); + srcu_read_unlock(&kvm->srcu, srcu_idx); vapic_exit(vcpu); @@ -4881,7 +4881,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) { - int r; + int srcu_idx, r; sigset_t sigsaved; if (vcpu->sigset_active) @@ -4905,9 +4905,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) vcpu->mmio_read_completed = 1; vcpu->mmio_needed = 0; } - vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); + srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); r = emulate_instruction(vcpu, 0, 0, EMULTYPE_NO_DECODE); - srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); + srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx); if (r != EMULATE_DONE) { r = 0; goto out; -- 1.7.3-rc1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
