tracing get_pages

Hi,

I'm trying to trace some guest physical pages by running:
cmd-trace record -e kvmmmu:kvm_mmu_get_page

However, when reporting I'm running into error messages like the following:

...
failed to read event print fmt for kvm_emulate_insn
Error: expected type 4 but read 7
Error: expected type 5 but read 0
failed to read event print fmt for kvm_userspace_exit
CPU 1 is empty
CPU 3 is empty
CPU 5 is empty
CPU 6 is empty
CPU 7 is empty
cpus=8
...
kvm-4851 [000] 20127.717022: kvm_mmu_get_page: [FAILED TO PARSE]
gfn=220672 role=122881 root_count=0 unsync=0 created=1

kvm-4851 [000] 20127.970428: kvm_mmu_get_page: [FAILED TO PARSE]
gfn=219136 role=122881 root_count=0 unsync=0 created=1

...

I don't have any problems with other events like pagetable_walk or paging_element.

This KVM is from Linus' latest tree, what am I doing wrong?

Thanks in advance,
Davidlohr