linux-kernel - [PATCH 3/4] kobject: validate ktype release function during add

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Message-Id: <20230311-kobject-warning-v1-3-1ebba4f71fb5@weissschuh.net>
Date:   Sat, 11 Mar 2023 03:14:48 +0000
From:   Thomas Weißschuh <linux@...ssschuh.net>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     linux-kernel@...r.kernel.org,
        Thomas Weißschuh <linux@...ssschuh.net>,
        Mirsad Todorovac <mirsad.todorovac@....unizg.hr>
Subject: [PATCH 3/4] kobject: validate ktype release function during add

Validating the ktype during cleanup is suboptimal.
Many kobjects are only destroyed during shutdown which makes it hard to
observe the messages.

Instead perform the validation when the object is added.

Reported-by: Mirsad Todorovac <mirsad.todorovac@....unizg.hr>
Link: https://lore.kernel.org/lkml/60b2b66c-22c9-1d38-ed1c-7b7d95e32720@alu.unizg.hr/
Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
---
 lib/kobject.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/kobject.c b/lib/kobject.c
index f79a434e1231..68ff8a48b784 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -215,6 +215,10 @@ static int kobject_add_internal(struct kobject *kobj)
 		return -EINVAL;
 	}
 
+	if (kobj->ktype && !kobj->ktype->release)
+		pr_debug("'%s' (%p): does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
+			 kobject_name(kobj), kobj);
+
 	parent = kobject_get(kobj->parent);
 
 	/* join kset if set, use it as parent if we do not already have one */
@@ -663,10 +667,6 @@ static void kobject_cleanup(struct kobject *kobj)
 	pr_debug("'%s' (%p): %s, parent %p\n",
 		 kobject_name(kobj), kobj, __func__, kobj->parent);
 
-	if (t && !t->release)
-		pr_debug("'%s' (%p): does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
-			 kobject_name(kobj), kobj);
-
 	/* remove from sysfs if the caller did not do it */
 	if (kobj->state_in_sysfs) {
 		pr_debug("'%s' (%p): auto cleanup kobject_del\n",

-- 
2.39.2