[PATCH 14/21] tracing: Add preempt disable for filter self test

Steven Rostedt
2011-09-22T22:13:16Z

[-- Attachment #1: 0014-tracing-Add-preempt-disable-for-filter-self-test.patch --]
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From: Steven Rostedt <srostedt@redhat.com>

The self testing for event filters does not really need preemption
disabled as there are no races at the time of testing, but the functions
it calls uses rcu_dereference_sched() which will complain if preemption
is not disabled.

Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_events_filter.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 6a642e2..816d3d0 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -2101,6 +2101,11 @@ static __init int ftrace_test_event_filter(void)
break;
}

+ /*
+ * The preemption disabling is not really needed for self
+ * tests, but the rcu dereference will complain without it.
+ */
+ preempt_disable();
if (*d->not_visited)
walk_pred_tree(filter->preds, filter->root,
test_walk_pred_cb,
@@ -2108,6 +2113,7 @@ static __init int ftrace_test_event_filter(void)

test_pred_visited = 0;
err = filter_match_preds(filter, &d->rec);
+ preempt_enable();

__free_filter(filter);

--
1.7.5.4