Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2119111

commit af735db3
Author: Coleman Dietsch <dietschc@csp.edu>
Date:   Mon Aug 8 14:06:06 2022 -0500

    KVM: x86/xen: Initialize Xen timer only once

    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: 53639526 ("KVM: x86/xen: handle PV timers oneshot mode")
    Cc: stable@vger.kernel.org
    Link: https://syzkaller.appspot.com/bug?id=8234a9dfd3aafbf092cc5a7cd9842e3ebc45fc42


Reported-by:  <syzbot+e54f930ed78eb0f85281@syzkaller.appspotmail.com>
Signed-off-by: Coleman Dietsch <dietschc@csp.edu>
Reviewed-by: Sean Christopherson <seanjc@google.com>
    Message-Id: <20220808190607.323899-2-dietschc@csp.edu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>