On 09/04/15 at 12:45pm, Sasha Levin wrote: > We don't init iter->started when dumping the ftrace buffer, and there's no > real need to do so - so allow skipping that check if the iter doesn't have > an initialized ->started cpumask. > > Signed-off-by: Sasha Levin <sasha.le...@oracle.com> > --- > kernel/trace/trace.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 6e79408..0dc647f 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -2671,13 +2671,14 @@ static void test_cpu_buff_start(struct trace_iterator > *iter) > if (!(iter->iter_flags & TRACE_FILE_ANNOTATE)) > return; > > - if (cpumask_test_cpu(iter->cpu, iter->started)) > + if (iter->started && cpumask_test_cpu(iter->cpu, iter->started)) > return;
Ftrace will initialize the variable iter->started in the function trace_init_global_iter. Otherwise kernel will panic during calling the function cpumask_test_cpu. So it is safe to call the function cpumask_test_cpu without doing checking. Thanks Minfei -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
