Add a check for existing xen timers before initializing a new one.
Currently kvm_xen_init_timer() is called on every KVM_XEN_VCPU_ATTR_TYPE_TIMER, which is causing the following ODEBUG crash when vcpu->arch.xen.timer is already set.
ODEBUG: init active (active state 0) object type: hrtimer hint: xen_timer_callbac0 RIP: 0010:debug_print_object+0x16e/0x250 lib/debugobjects.c:502 Call Trace: __debug_object_init debug_hrtimer_init debug_init hrtimer_init kvm_xen_init_timer kvm_xen_vcpu_set_attr kvm_arch_vcpu_ioctl kvm_vcpu_ioctl vfs_ioctl
Fixes: 536395260582 ("KVM: x86/xen: handle PV timers oneshot mode") Cc: stable@vger.kernel.org Link: https://syzkaller.appspot.com/bug?id=8234a9dfd3aafbf092cc5a7cd9842e3ebc45fc4... Reported-by: syzbot+e54f930ed78eb0f85281@syzkaller.appspotmail.com Signed-off-by: Coleman Dietsch dietschc@csp.edu --- arch/x86/kvm/xen.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index a0c05ccbf4b1..6e554041e862 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -713,7 +713,9 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) break; } vcpu->arch.xen.timer_virq = data->u.timer.port; - kvm_xen_init_timer(vcpu); + + if (!vcpu->arch.xen.timer.function) + kvm_xen_init_timer(vcpu);
/* Restart the timer if it's set */ if (data->u.timer.expires_ns)