1 files changed, 19 insertions, 10 deletions

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index ca9c13b2ecf4..5e8c07aef071 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -42,10 +42,13 @@ enum { ERRORS };
 
 static const char *err_text[] = { ERRORS };
 
-static char last_cmd[MAX_FILTER_STR_VAL];
+static char *last_cmd;
 
 static int errpos(const char *str)
 {
+	if (!str || !last_cmd)
+		return 0;
+
 	return err_pos(last_cmd, str);
 }
 
@@ -54,11 +57,16 @@ static void last_cmd_set(const char *str)
 	if (!str)
 		return;
 
-	strncpy(last_cmd, str, MAX_FILTER_STR_VAL - 1);
+	kfree(last_cmd);
+
+	last_cmd = kstrdup(str, GFP_KERNEL);
 }
 
-static void synth_err(u8 err_type, u8 err_pos)
+static void synth_err(u8 err_type, u16 err_pos)
 {
+	if (!last_cmd)
+		return;
+
 	tracing_log_err(NULL, "synthetic_events", last_cmd, err_text,
 			err_type, err_pos);
 }
@@ -1979,7 +1987,7 @@ EXPORT_SYMBOL_GPL(synth_event_add_next_val);
 /**
  * synth_event_add_val - Add a named field's value to an open synth trace
  * @field_name: The name of the synthetic event field value to set
- * @val: The value to set the next field to
+ * @val: The value to set the named field to
  * @trace_state: A pointer to object tracking the piecewise trace state
  *
  * Set the value of the named field in an event that's been opened by
@@ -2054,6 +2062,13 @@ static int create_synth_event(const char *raw_command)
 
 	last_cmd_set(raw_command);
 
+	name = raw_command;
+
+	/* Don't try to process if not our system */
+	if (name[0] != 's' || name[1] != ':')
+		return -ECANCELED;
+	name += 2;
+
 	p = strpbrk(raw_command, " \t");
 	if (!p) {
 		synth_err(SYNTH_ERR_INVALID_CMD, 0);
@@ -2062,12 +2077,6 @@ static int create_synth_event(const char *raw_command)
 
 	fields = skip_spaces(p);
 
-	name = raw_command;
-
-	if (name[0] != 's' || name[1] != ':')
-		return -ECANCELED;
-	name += 2;
-
 	/* This interface accepts group name prefix */
 	if (strchr(name, '/')) {
 		len = str_has_prefix(name, SYNTH_SYSTEM "/");