Re: [PATCH v3 1/2] KVM: x86/xen: Initialize Xen timer only once

[Sean Christopherson]

On Mon, Aug 08, 2022, Coleman Dietsch wrote:
> 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@xxxxxxxxxxxxxxx
> Link: https://syzkaller.appspot.com/bug?id=8234a9dfd3aafbf092cc5a7cd9842e3ebc45fc42
> Reported-by: syzbot+e54f930ed78eb0f85281@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Coleman Dietsch <dietschc@xxxxxxx>
> ---

Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>