[PATCH] Revert "kobject: Remove redundant checks for whether ktype is NULL"

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

This reverts commit 1b28cb81dab7c1eedc6034206f4e8d644046ad31.

It is reported to cause problems, so revert it for now until the root
cause can be found.

Reported-by: kernel test robot <oliver.sang@intel.com>
Fixes: 1b28cb81dab7 ("kobject: Remove redundant checks for whether ktype is NULL")
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Closes: https://lore.kernel.org/oe-lkp/202402071403.e302e33a-oliver.sang@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 lib/kobject.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/lib/kobject.c b/lib/kobject.c
index 59dbcbdb1c91..72fa20f405f1 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -74,10 +74,12 @@ static int create_dir(struct kobject *kobj)
 	if (error)
 		return error;
 
-	error = sysfs_create_groups(kobj, ktype->default_groups);
-	if (error) {
-		sysfs_remove_dir(kobj);
-		return error;
+	if (ktype) {
+		error = sysfs_create_groups(kobj, ktype->default_groups);
+		if (error) {
+			sysfs_remove_dir(kobj);
+			return error;
+		}
 	}
 
 	/*
@@ -589,7 +591,8 @@ static void __kobject_del(struct kobject *kobj)
 	sd = kobj->sd;
 	ktype = get_ktype(kobj);
 
-	sysfs_remove_groups(kobj, ktype->default_groups);
+	if (ktype)
+		sysfs_remove_groups(kobj, ktype->default_groups);
 
 	/* send "remove" if the caller did not do it but sent "add" */
 	if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
@@ -666,6 +669,10 @@ 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",
@@ -676,13 +683,10 @@ static void kobject_cleanup(struct kobject *kobj)
 		parent = NULL;
 	}
 
-	if (t->release) {
+	if (t && t->release) {
 		pr_debug("'%s' (%p): calling ktype release\n",
 			 kobject_name(kobj), kobj);
 		t->release(kobj);
-	} else {
-		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);
 	}
 
 	/* free name if we allocated it */
@@ -1056,7 +1060,7 @@ const struct kobj_ns_type_operations *kobj_child_ns_ops(const struct kobject *pa
 {
 	const struct kobj_ns_type_operations *ops = NULL;
 
-	if (parent && parent->ktype->child_ns_type)
+	if (parent && parent->ktype && parent->ktype->child_ns_type)
 		ops = parent->ktype->child_ns_type(parent);
 
 	return ops;
-- 
2.43.0