[PATCH v2 3/4] tracing: Add 'hist:' to hist trigger error log error string

[Tom Zanussi <zanussi@kernel.org>]

The 'hist:' prefix gets stripped from the command text during command
processing, but should be added back when displaying the command
during error processing.

Not only because it's what should be displayed but also because not
having it means the test cases fail because the caret is miscalculated
by the length of the prefix string.

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 kernel/trace/trace_events_hist.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index d33c94a1cfa9..79768f22d5c5 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -607,7 +607,8 @@ static void last_cmd_set(struct trace_event_file *file, char *str)
 	if (!str)
 		return;
 
-	strncpy(last_cmd, str, MAX_FILTER_STR_VAL - 1);
+	strcpy(last_cmd, "hist:");
+	strncat(last_cmd, str, MAX_FILTER_STR_VAL - 1 - sizeof("hist:"));
 
 	if (file) {
 		call = file->event_call;
-- 
2.14.1