[PATCH v2 1/7] tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()

["Thomas Weißschuh" <thomas.weissschuh@linutronix.de>]

While ftrace_set_clr_event() modifies its input buffer during parsing,
before returning to the caller the buffer is supposed to be restored
to its original state.

This works correctly for the colon between the subsystem and event
but not the colon at the beginning of :mod:.

Restore the colon, so the :mod: trailer is not stripped after
ftrace_set_clr_event().

Fixes: 4c86bc531e60 ("tracing: Add :mod: command to enabled module events")
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 kernel/trace/trace_events.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 1d39eaf6a0f7..eab653cb3540 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1489,6 +1489,8 @@ int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
 	/* Put back the colon to allow this to be called again */
 	if (buf)
 		*(buf - 1) = ':';
+	if (mod)
+		*(mod - 5) = ':';
 
 	return ret;
 }

-- 
2.55.0