On Tue, Feb 09, 2016 at 07:49:05PM +0300, Denis V. Lunev wrote:
> we should call trace_init_backends() before trace_init_file() for
> CONFIG_TRACE_SIMPLE There is no difference for other cases.
> 
> This problem was introduced by the commit
>     commit 41fc57e44ed64cd4ab5393d83624afd897dabd4f
>     Author: Paolo Bonzini <pbonzini@redhat.com>
>     Date:   Thu Jan 7 16:55:24 2016 +0300
> 
>     trace: split trace_init_file out of trace_init_backends
> 
> 'make check' was failed as a result if configured with
>   --enable-trace-backends=simple
> 
> Spotted by Alex Bennée.
> 
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Alex Bennée <alex.bennee@linaro.org>
> CC: Paolo Bonzini <pbonzini@redhat.com>
> CC: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  vl.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)

Thanks, applied to my tracing tree:
https://github.com/stefanha/qemu/commits/tracing

Stefan