Commit eb7511bf authored by Haimin Zhang's avatar Haimin Zhang Committed by Paolo Bonzini

KVM: x86: Handle SRCU initialization failure during page track init

Check the return of init_srcu_struct(), which can fail due to OOM, when
initializing the page track mechanism.  Lack of checking leads to a NULL
pointer deref found by a modified syzkaller.
Reported-by: default avatarTCS Robot <tcs_robot@tencent.com>
Signed-off-by: default avatarHaimin Zhang <tcs_kernel@tencent.com>
Message-Id: <1630636626-12262-1-git-send-email-tcs_kernel@tencent.com>
[Move the call towards the beginning of kvm_arch_init_vm. - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent cd36ae87
......@@ -46,7 +46,7 @@ struct kvm_page_track_notifier_node {
struct kvm_page_track_notifier_node *node);
};
void kvm_page_track_init(struct kvm *kvm);
int 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 *slot);
......
......@@ -164,13 +164,13 @@ void kvm_page_track_cleanup(struct kvm *kvm)
cleanup_srcu_struct(&head->track_srcu);
}
void kvm_page_track_init(struct kvm *kvm)
int kvm_page_track_init(struct kvm *kvm)
{
struct kvm_page_track_notifier_head *head;
head = &kvm->arch.track_notifier_head;
init_srcu_struct(&head->track_srcu);
INIT_HLIST_HEAD(&head->track_notifier_list);
return init_srcu_struct(&head->track_srcu);
}
/*
......
......@@ -11144,9 +11144,15 @@ void kvm_arch_free_vm(struct kvm *kvm)
int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
int ret;
if (type)
return -EINVAL;
ret = kvm_page_track_init(kvm);
if (ret)
return ret;
INIT_HLIST_HEAD(&kvm->arch.mask_notifier_list);
INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);
INIT_LIST_HEAD(&kvm->arch.zapped_obsolete_pages);
......@@ -11179,7 +11185,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
kvm_apicv_init(kvm);
kvm_hv_init_vm(kvm);
kvm_page_track_init(kvm);
kvm_mmu_init_vm(kvm);
kvm_xen_init_vm(kvm);
......
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