[PATCH 1/2] tracing: Return -ENOENT if there is no target synthetic event

[PATCH 1/2] tracing: Return -ENOENT if there is no target synthetic event

[Masami Hiramatsu]

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

Fixes: 4b147936fa50 ('tracing: Add support for 'synthetic' events')
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Steven Rostedt <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;

[PATCH 2/2] selftests/ftrace: Fix synthetic event test to delete event correctly

[Masami Hiramatsu]

Fix the synthetic event test case to remove event correctly.
If redirecting command to synthetic_event file without append
mode, it cleans up all existing events and execute (parse) the
command. This means "delete event" always fails to find the
target event.

Since previous synthetic event has a bug which doesn't return
-ENOENT even if it fails to find the deleting event, this test
passed. But fixing that bug, this test fails because this test
itself has a bug.

This fixes that bug by trying to delete event right after
adding an event, and use append mode redirection ('>>') instead
of normal redirection ('>').

Fixes: f06eec4d0f2c ('selftests: ftrace: Add inter-event hist triggers testcases')
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Cc: Rajvi Jingar <rajvi.jingar@intel.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 .../trigger-synthetic-event-createremove.tc        |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-createremove.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-createremove.tc
index cef11377dcbd..c604438df13b 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-createremove.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-createremove.tc
@@ -35,18 +35,18 @@ fi
 
 reset_trigger
 
-echo "Test create synthetic event with an error"
-echo 'wakeup_latency  u64 lat pid_t pid char' > synthetic_events > /dev/null
+echo "Test remove synthetic event"
+echo '!wakeup_latency  u64 lat pid_t pid char comm[16]' >> synthetic_events
 if [ -d events/synthetic/wakeup_latency ]; then
-    fail "Created wakeup_latency synthetic event with an invalid format"
+    fail "Failed to delete wakeup_latency synthetic event"
 fi
 
 reset_trigger
 
-echo "Test remove synthetic event"
-echo '!wakeup_latency  u64 lat pid_t pid char comm[16]' > synthetic_events
+echo "Test create synthetic event with an error"
+echo 'wakeup_latency  u64 lat pid_t pid char' > synthetic_events > /dev/null
 if [ -d events/synthetic/wakeup_latency ]; then
-    fail "Failed to delete wakeup_latency synthetic event"
+    fail "Created wakeup_latency synthetic event with an invalid format"
 fi
 
 do_reset

[PATCH 2/2] selftests/ftrace: Fix synthetic event test to delete event correctly

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Fix the synthetic event test case to remove event correctly.
If redirecting command to synthetic_event file without append
mode, it cleans up all existing events and execute (parse) the
command. This means "delete event" always fails to find the
target event.

Since previous synthetic event has a bug which doesn't return
-ENOENT even if it fails to find the deleting event, this test
passed. But fixing that bug, this test fails because this test
itself has a bug.

This fixes that bug by trying to delete event right after
adding an event, and use append mode redirection ('>>') instead
of normal redirection ('>').

Link: http://lkml.kernel.org/r/154013452832.25576.2305459545429386517.stgit@devbox

Acked-by: Shuah Khan <shuah@kernel.org>
Acked-by: Tom Zanussi <zanussi@linux.intel.com>
Tested-by: Tom Zanussi <zanussi@linux.intel.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Rajvi Jingar <rajvi.jingar@intel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: stable@vger.kernel.org
Fixes: f06eec4d0f2c ('selftests: ftrace: Add inter-event hist triggers testcases')
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 .../trigger-synthetic-event-createremove.tc          | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-createremove.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-createremove.tc
index cef11377dcbd..c604438df13b 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-createremove.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-createremove.tc
@@ -35,18 +35,18 @@ fi
 
 reset_trigger
 
-echo "Test create synthetic event with an error"
-echo 'wakeup_latency  u64 lat pid_t pid char' > synthetic_events > /dev/null
+echo "Test remove synthetic event"
+echo '!wakeup_latency  u64 lat pid_t pid char comm[16]' >> synthetic_events
 if [ -d events/synthetic/wakeup_latency ]; then
-    fail "Created wakeup_latency synthetic event with an invalid format"
+    fail "Failed to delete wakeup_latency synthetic event"
 fi
 
 reset_trigger
 
-echo "Test remove synthetic event"
-echo '!wakeup_latency  u64 lat pid_t pid char comm[16]' > synthetic_events
+echo "Test create synthetic event with an error"
+echo 'wakeup_latency  u64 lat pid_t pid char' > synthetic_events > /dev/null
 if [ -d events/synthetic/wakeup_latency ]; then
-    fail "Failed to delete wakeup_latency synthetic event"
+    fail "Created wakeup_latency synthetic event with an invalid format"
 fi
 
 do_reset
-- 
2.19.0