x86, bts: wait until traced task has been scheduled out
authorMarkus Metzger <markus.t.metzger@intel.com>
Fri, 3 Apr 2009 14:43:36 +0000 (16:43 +0200)
committerIngo Molnar <mingo@elte.hu>
Tue, 7 Apr 2009 11:36:15 +0000 (13:36 +0200)
commit8d99b3ac2726e5edd97ad147fa5c1f2acb63a745
tree764aa40840c18187ca11a7b0baf3e24edcc40ec9
parente2b371f00a6f529f6362654239bdec8dcd510760
x86, bts: wait until traced task has been scheduled out

In order to stop branch tracing for a running task, we need to first
clear the branch tracing control bits before we may free the tracing
buffer.

If the traced task is running, the cpu might still trace that task
after the branch trace control bits have cleared.

Wait until the traced task has been scheduled out before proceeding.

A similar problem affects the task debug store context. We first remove
the context, then we need to wait until the task has been scheduled
out before we can free the context memory.

Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Cc: roland@redhat.com
Cc: eranian@googlemail.com
Cc: juan.villacis@intel.com
Cc: ak@linux.jf.intel.com
LKML-Reference: <20090403144551.919636000@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/kernel/ds.c