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authorChunyu Hu <chuhu@redhat.com>2016-05-03 19:34:34 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-05-11 11:21:00 +0200
commit9ae8b1a1c6dbac37e4c4cd2dd34ada9866bf3e84 (patch)
tree2e51d7976c1be68b9f5c5ff9419a342362cb0867
parent4a4b98101f7bd04d6353677230ca622e3324b541 (diff)
downloadlwn-9ae8b1a1c6dbac37e4c4cd2dd34ada9866bf3e84.tar.gz
lwn-9ae8b1a1c6dbac37e4c4cd2dd34ada9866bf3e84.zip
tracing: Don't display trigger file for events that can't be enabled
commit 854145e0a8e9a05f7366d240e2f99d9c1ca6d6dd upstream. Currently register functions for events will be called through the 'reg' field of event class directly without any check when seting up triggers. Triggers for events that don't support register through debug fs (events under events/ftrace are for trace-cmd to read event format, and most of them don't have a register function except events/ftrace/functionx) can't be enabled at all, and an oops will be hit when setting up trigger for those events, so just not creating them is an easy way to avoid the oops. Link: http://lkml.kernel.org/r/1462275274-3911-1-git-send-email-chuhu@redhat.com Fixes: 85f2b08268c01 ("tracing: Add basic event trigger framework") Signed-off-by: Chunyu Hu <chuhu@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/trace/trace_events.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index bb1ac9cbe30a..a8bd1ca97e03 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1546,8 +1546,13 @@ event_create_dir(struct dentry *parent, struct ftrace_event_file *file)
trace_create_file("filter", 0644, file->dir, file,
&ftrace_event_filter_fops);
- trace_create_file("trigger", 0644, file->dir, file,
- &event_trigger_fops);
+ /*
+ * Only event directories that can be enabled should have
+ * triggers.
+ */
+ if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
+ trace_create_file("trigger", 0644, file->dir, file,
+ &event_trigger_fops);
trace_create_file("format", 0444, file->dir, call,
&ftrace_event_format_fops);