of: do not use "%pOF" printk format on node with refcount of zero

of_node_release() can not use the "%pOF" printk format to report
the node name of a node when the node reference count is zero.
This is because the formatter device_node_string() calls
fwnode_full_name_string() which indirectly calls of_node_get().
Calling of_node_get() on the node with a zero reference count
results in a WARNING and stack trace.

When the reference count has been decremented to zero, this function
is in the subsequent call path which frees memory related to the node.

This commit resolves the unittest EXPECT errors that were created in
the previous commmit.

Signed-off-by: Frank Rowand <frowand.list@gmail.com>
Link: https://lore.kernel.org/r/20230213185702.395776-6-frowand.list@gmail.com
Signed-off-by: Rob Herring <robh@kernel.org>

diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index becb80f762c8e3183db193c3c5a6967f5ad4f55c..dbcbc41f34651c3f6471f3c31fdaf86c2c0f1585 100644 (file)
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -329,9 +329,17 @@ void of_node_release(struct kobject *kobj)
 {
        struct device_node *node = kobj_to_device_node(kobj);
 
+       /*
+        * can not use '"%pOF", node' in pr_err() calls from this function
+        * because an of_node_get(node) when refcount is already zero
+        * will result in an error and a stack dump
+        */
+
        /* We should never be releasing nodes that haven't been detached. */
        if (!of_node_check_flag(node, OF_DETACHED)) {
-               pr_err("ERROR: Bad of_node_put() on %pOF\n", node);
+
+               pr_err("ERROR: %s() detected bad of_node_put() on %pOF/%s\n",
+                       __func__, node->parent, node->full_name);
 
                /*
                 * of unittests will test this path.  Do not print the stack