tracing: Decrement trace_array when bootconfig creates an instance

The trace_array_get_by_name() creates a ftrace instance and
trace_array_put() is used to remove the reference. Even though the
trace_array_get_by_name() creates the instance, it also adds a reference
count to it, that prevents user space from removing it.

As the bootconfig just creates the instance on boot up, it should still be
used where it can be deleted by user space after boot. A trace_array_put()
is required to let that happen.

Also, change the documentation on trace_array_get_by_name() to make this not
be so confusing.

Link: https://lore.kernel.org/r/20200124205927.76128804@rorschach.local.home

Fixes: 4f712a4d04a4e ("tracing/boot: Add instance node support")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index cd541ac1cbc1..2f616cd926b0 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -327,6 +327,7 @@ trace_boot_init_instances(struct xbc_node *node)
 			continue;
 		}
 		trace_boot_init_one_instance(tr, inode);
+		trace_array_put(tr);
 	}
 }