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Commit 452a68d0 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: hyperv: idr_find needs RCU protection 



Even though the eventfd is released after the KVM SRCU grace period
elapses, the conn_to_evt data structure itself is not; it uses RCU
internally, instead.  Fix the read-side critical section to happen
under rcu_read_lock/unlock; the result is still protected by
vcpu->kvm->srcu.

Reviewed-by: default avatarRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 6356ee0c

arch/x86/kvm/hyperv.c

+3 −1
Original line number Diff line number Diff line
@@ -1296,8 +1296,10 @@ static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, bool fast, u64 param) 
	if (param & ~KVM_HYPERV_CONN_ID_MASK)

		return HV_STATUS_INVALID_HYPERCALL_INPUT;



	/* conn_to_evt is protected by vcpu->kvm->srcu */

	/* the eventfd is protected by vcpu->kvm->srcu, but conn_to_evt isn't */

	rcu_read_lock();

	eventfd = idr_find(&vcpu->kvm->arch.hyperv.conn_to_evt, param);

	rcu_read_unlock();

	if (!eventfd)

		return HV_STATUS_INVALID_PORT_ID;