tracing: Do not free iter->trace in fail path of tracing_open_pipe()

commit e7f0c42 upstream.

Commit d716ff7 ("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/[email protected]

Cc: [email protected]
Fixes: d716ff7 ("tracing: Remove taking of trace_types_lock in pipe files")
Signed-off-by: zhangyi (F) <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: zhangyi089

kernel/trace/trace.c

@@ -5057,7 +5057,6 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
 	return ret;
 
 fail:
-	kfree(iter->trace);
 	kfree(iter);
 	__trace_array_put(tr);
 	mutex_unlock(&trace_types_lock);