x86, bts: reenable ptrace branch trace support
The races found by Oleg Nesterov have been fixed.
Reenable branch trace support.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
LKML-Reference: <20090424094448.A30216@sedona.ch.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>