3.16.46-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Peter Xu <[email protected]> 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 <[email protected]> Signed-off-by: Radim Krčmář <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> --- virt/kvm/kvm_main.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -606,8 +606,10 @@ static void kvm_destroy_vm(struct kvm *k list_del(&kvm->vm_list); 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); @@ -3011,6 +3013,14 @@ int kvm_io_bus_unregister_dev(struct kvm 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) {
