From: Mark McLoughlin Date: Mon, 1 Dec 2008 13:57:46 +0000 (+0000) Subject: KVM: make kvm_unregister_irq_ack_notifier() safe X-Git-Tag: firefly_0821_release~16439^2~37 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=fdd897e6b5253a45b633f7d334cf3e150bbaf386;p=firefly-linux-kernel-4.4.55.git KVM: make kvm_unregister_irq_ack_notifier() safe We never pass a NULL notifier pointer here, but we may well pass a notifier struct which hasn't previously been registered. Guard against this by using hlist_del_init() which will not do anything if the node hasn't been added to the list and, when removing the node, will ensure that a subsequent call to hlist_del_init() will be fine too. Fixes an oops seen when an assigned device is freed before and IRQ is assigned to it. Signed-off-by: Mark McLoughlin Signed-off-by: Avi Kivity --- diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c index 973df997ea60..db75045f22f6 100644 --- a/virt/kvm/irq_comm.c +++ b/virt/kvm/irq_comm.c @@ -63,9 +63,7 @@ void kvm_register_irq_ack_notifier(struct kvm *kvm, void kvm_unregister_irq_ack_notifier(struct kvm_irq_ack_notifier *kian) { - if (!kian) - return; - hlist_del(&kian->link); + hlist_del_init(&kian->link); } /* The caller must hold kvm->lock mutex */