>
> Note 2: I get output of the form
>
> ... kvm_emulate_insn: 0:fffff800010527b5: mov $0x0, 0xfffe00b0CAN'T FIND FIELD "guest_rip"
>
> which leads me to believe there is a bug in trace_seq_printf when the input
> to %s is "".
I ran this under gdb (nice to do that, where I don't in kernel :-) And
it takes me to kvm_emulate_insn_handler() which does the
trace_seq_printf() fine, but then calls pevent_print_num_field() and
that passes in "guest_rip" where we get the "CAN'T FIND FIELD" error.
In pevent_print_num_field() it searches for "guest_rip" at the top of
the function (pevent_find_field()), but the event kvm_emulate_insn does
not have a "guest_rip" field, then it jumps to the error message.