It is possible that the testing thread in the ftrace wakeup test does not run before we stop the trace. This will cause the trace to fail since nothing will be in the buffers. This patch adds a small wait in the wakeup test to allow for the woken task to run and be traced. Signed-off-by: Steven Rostedt --- kernel/trace/trace_selftest.c | 3 +++ 1 file changed, 3 insertions(+) Index: linux-tip.git/kernel/trace/trace_selftest.c =================================================================== --- linux-tip.git.orig/kernel/trace/trace_selftest.c 2008-09-29 20:13:37.000000000 -0400 +++ linux-tip.git/kernel/trace/trace_selftest.c 2008-09-29 20:14:30.000000000 -0400 @@ -498,6 +498,9 @@ trace_selftest_startup_wakeup(struct tra wake_up_process(p); + /* give a little time to let the thread wake up */ + msleep(100); + /* stop the tracing. */ tr->ctrl = 0; trace->ctrl_update(tr); --