KVM: x86: clear bus pointer when destroyed
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 <peterx@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e013f90..5f7bff5 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -614,8 +614,10 @@
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);
@@ -3083,6 +3085,14 @@
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) {