From dd8db8538c8aee325e08d65843d0824e4ee03938 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Wed, 15 Mar 2017 16:01:17 +0800 Subject: [PATCH] KVM: x86: clear bus pointer when destroyed MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit df630b8c1e851b5e265dc2ca9c87222e342c093b upstream. When releasing the bus, let's clear the bus pointers to mark it out. If any further device unregister happens on this bus, we know that we're done if we found the bus being released already. Signed-off-by: Peter Xu Signed-off-by: Radim Krčmář Signed-off-by: Willy Tarreau --- virt/kvm/kvm_main.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index f71c4ad425c6..e9128725ff11 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -607,8 +607,10 @@ static void kvm_destroy_vm(struct kvm *kvm) list_del(&kvm->vm_list); raw_spin_unlock(&kvm_lock); kvm_free_irq_routing(kvm); - for (i = 0; i < KVM_NR_BUSES; i++) + for (i = 0; i < KVM_NR_BUSES; i++) { kvm_io_bus_destroy(kvm->buses[i]); + kvm->buses[i] = NULL; + } kvm_coalesced_mmio_free(kvm); #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER) mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm); @@ -2959,6 +2961,14 @@ int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx, struct kvm_io_bus *new_bus, *bus; bus = kvm->buses[bus_idx]; + + /* + * It's possible the bus being released before hand. If so, + * we're done here. + */ + if (!bus) + return 0; + r = -ENOENT; for (i = 0; i < bus->dev_count; i++) if (bus->range[i].dev == dev) { -- 2.20.1