tracing: Add 'hist:' to hist trigger error log error string

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>

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 23458ba9e5f52a8df4fd0c880cd202ceba1a48a0..c322826e07265dc3a83ec2ba04abec6e73b2946d 100644 (file)
--- 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;