From: Masami Hiramatsu mhiramat@kernel.org

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

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index d239004aaf29..eb908ef2ecec 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -1063,8 +1063,10 @@ static int create_synth_event(int argc, char **argv) event = NULL; ret = -EEXIST; goto out; - } else if (delete_event) + } else if (delete_event) { + ret = -ENOENT; goto out; + }

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