FAILED: patch "[PATCH] KVM: x86: cleanup the page tracking SRCU instance" failed to apply to 4.9-stable tree

From 2beb6dad2e8f95d710159d5befb390e4f62ab5cf Mon Sep 17 00:00:00 2001

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 2beb6dad2e8f95d710159d5befb390e4f62ab5cf Mon Sep 17 00:00:00 2001

From: Paolo Bonzini <[email protected]>
Date: Mon, 27 Mar 2017 17:53:50 +0200
Subject: [PATCH] KVM: x86: cleanup the page tracking SRCU instance

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 <[email protected]>

Suggested-by Dmitry Vyukov <[email protected]>

Cc [email protected]

Fixes 0eb05bf290cfe8610d9680b49abef37febd1c38a

Reviewed-by Xiao Guangrong <[email protected]>

Signed-off-by Paolo Bonzini <[email protected]>

arch/x86/include/asm/kvm_page_track.h +1 -0

index d74747b031ec..c4eda791f877 100644
@@ -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);

arch/x86/kvm/page_track.c +8 -0

index 37942e419c32..60168cdd0546 100644
@@ -160,6 +160,14 @@ bool kvm_page_track_is_active(struct kvm_vcpu *vcpu, gfn_t gfn,
 	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;

arch/x86/kvm/x86.c +1 -0

index 64697fe475c3..ccbd45ecd41a 100644
@@ -8158,6 +8158,7 @@ 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,