On 2 November 2016 at 17:34, Stefano Stabellini <sstabell...@kernel.org> wrote: > On Wed, 2 Nov 2016, Thomas Huth wrote: >> Olaf Hering reported a build failure due to an undefined reference >> to 'qemu_log_vprintf'. Explicitely including qemu/log.h seems to >> fix the issue. >> >> Signed-off-by: Thomas Huth <th...@redhat.com> > > The fix makes sense: > > Acked-by: Stefano Stabellini <sstabell...@kernel.org> > > However I was unable to reproduce the build failure, so I would like a > confirmation from Olaf that the fix is working.
If you configure with the (default) simple trace backend then trace.h will pull in qemu/log.h (and in this case trace.h comes in via xen_common.h). But if you're using a different backend then it won't bring in that header, and you'll get the build failure. This is a fairly common "breaks but only with some trace backends" compile failure, but I'm not sure how best to try to make it more robust (or at least into a 'fails-everywhere' bug). thanks -- PMM