[PATCH 4/6] tracing: Have current_trace inc the trace array ref count

[Steven Rostedt]

From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>

The current_trace updates the trace array tracer. For an instance, if the
file is opened and the instance is deleted, reading or writing to the file
will cause a use after free.

Up the ref count of the trace array when current_trace is opened.

Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@xxxxxxxxxx/

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 8530dec63e7b4 ("tracing: Add tracing_check_open_get_tr()")
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
 kernel/trace/trace.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c8b8b4c6feaf..b82df33d20ff 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -7791,10 +7791,11 @@ static const struct file_operations tracing_max_lat_fops = {
 #endif
 
 static const struct file_operations set_tracer_fops = {
-	.open		= tracing_open_generic,
+	.open		= tracing_open_generic_tr,
 	.read		= tracing_set_trace_read,
 	.write		= tracing_set_trace_write,
 	.llseek		= generic_file_llseek,
+	.release	= tracing_release_generic_tr,
 };
 
 static const struct file_operations tracing_pipe_fops = {
-- 
2.40.1