[PATCH 4.19 141/280] tracing: Do not free iter->trace in fail path of tracing_open_pipe()

[Greg Kroah-Hartman]

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: zhangyi (F) <yi.zhang@xxxxxxxxxx>

commit e7f0c424d0806b05d6f47be9f202b037eb701707 upstream.

Commit d716ff71dd12 ("tracing: Remove taking of trace_types_lock in
pipe files") use the current tracer instead of the copy in
tracing_open_pipe(), but it forget to remove the freeing sentence in
the error path.

There's an error path that can call kfree(iter->trace) after the iter->trace
was assigned to tr->current_trace, which would be bad to free.

Link: http://lkml.kernel.org/r/1550060946-45984-1-git-send-email-yi.zhang@xxxxxxxxxx

Cc: stable@xxxxxxxxxxxxxxx
Fixes: d716ff71dd12 ("tracing: Remove taking of trace_types_lock in pipe files")
Signed-off-by: zhangyi (F) <yi.zhang@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 kernel/trace/trace.c |    1 -
 1 file changed, 1 deletion(-)

--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5606,7 +5606,6 @@ out:
 	return ret;
 
 fail:
-	kfree(iter->trace);
 	kfree(iter);
 	__trace_array_put(tr);
 	mutex_unlock(&trace_types_lock);