[PATCH 4.18 316/350] tracing: Return -ENOENT if there is no target synthetic event

Greg Kroah-Hartman
2018-11-11T22:32:02Z

From: Masami Hiramatsu <mhiramat@kernel.org>

commit 18858511fd8a877303cc34c06efa461b26a0e070 upstream.

Return -ENOENT error if there is no target synthetic event.
This notices an operation failure to user as below;

# echo 'wakeup_latency u64 lat; pid_t pid;' > synthetic_events
# echo '!wakeup' >> synthetic_events
sh: write error: No such file or directory

Link: http://lkml.kernel.org/r/154013449986.25576.9487131386597290172.stgit@devbox

Acked-by: Tom Zanussi <zanussi@linux.intel.com>
Tested-by: Tom Zanussi <zanussi@linux.intel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Rajvi Jingar <rajvi.jingar@intel.com>
Cc: stable@vger.kernel.org
Fixes: 4b147936fa50 ('tracing: Add support for 'synthetic' events')
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/trace/trace_events_hist.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1072,8 +1072,10 @@ static int create_synth_event(int argc,
event = NULL;
ret = -EEXIST;
goto out;
- } else if (delete_event)
+ } else if (delete_event) {
+ ret = -ENOENT;
goto out;
+ }

if (argc < 2) {
ret = -EINVAL;