From: Tom Zanussi <zanussi@kernel.org>
Date: Fri, 28 Jun 2019 12:40:22 -0500
Subject: tracing: Add 'hist:' to hist trigger error log error string
Git-commit: d0a497066f92eee6e5750af6a0ca32866030931a
Patch-mainline: v5.6-rc1
References: bsc#1164917

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.

Link: http://lkml.kernel.org/r/449df721f560042e22382f67574bcc5b4d830d3d.1561743018.git.zanussi@kernel.org

Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Miroslav Benes <mbenes@suse.cz>
---
 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 23458ba9e5f5..c322826e0726 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -612,7 +612,8 @@ 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;