[PATCH 4.10 05/17] KVM: x86: cleanup the page tracking SRCU instance

Greg Kroah-Hartman
2017-03-30T10:01:18Z

From: Paolo Bonzini <pbonzini@redhat.com>

commit 2beb6dad2e8f95d710159d5befb390e4f62ab5cf upstream.

SRCU uses a delayed work item. Skip cleaning it up, and
the result is use-after-free in the work item callbacks.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: 0eb05bf290cfe8610d9680b49abef37febd1c38a
Reviewed-by: Xiao Guangrong <xiaoguangrong.eric@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/include/asm/kvm_page_track.h | 1 +
arch/x86/kvm/page_track.c | 8 ++++++++
arch/x86/kvm/x86.c | 1 +
3 files changed, 10 insertions(+)

--- a/arch/x86/include/asm/kvm_page_track.h
+++ b/arch/x86/include/asm/kvm_page_track.h
@@ -46,6 +46,7 @@ struct kvm_page_track_notifier_node {
};

void kvm_page_track_init(struct kvm *kvm);
+void kvm_page_track_cleanup(struct kvm *kvm);

void kvm_page_track_free_memslot(struct kvm_memory_slot *free,
struct kvm_memory_slot *dont);
--- a/arch/x86/kvm/page_track.c
+++ b/arch/x86/kvm/page_track.c
@@ -158,6 +158,14 @@ bool kvm_page_track_is_active(struct kvm
return !!ACCESS_ONCE(slot->arch.gfn_track[mode][index]);
}

+void kvm_page_track_cleanup(struct kvm *kvm)
+{
+ struct kvm_page_track_notifier_head *head;
+
+ head = &kvm->arch.track_notifier_head;
+ cleanup_srcu_struct(&head->track_srcu);
+}
+
void kvm_page_track_init(struct kvm *kvm)
{
struct kvm_page_track_notifier_head *head;
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8052,6 +8052,7 @@ void kvm_arch_destroy_vm(struct kvm *kvm
kvm_free_vcpus(kvm);
kvfree(rcu_dereference_check(kvm->arch.apic_map, 1));
kvm_mmu_uninit_vm(kvm);
+ kvm_page_track_cleanup(kvm);
}

void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,